user8673: A serious threat to human chess competition seems to be phone-in-the-bathroom cheating. Is anything being done to address this problem?

user3757: FIDE has proposed an Internet-based Game Screening Tool (see here for more information) in order to identify possible cases of cheating by assessing how much computer-like a player has played.

user12523: The Continental Chess Association (USA) has the following rule for its biggest tournaments:

A table will usually be provided near the bathroom for players to
  temporarily check devices. If such a table is provided, players may
  not possess devices inside the bathroom. See rule 10 for penalties.
  Players whose games have finished and spectators are also not allowed
  to possess devices in bathrooms. Cellphone detecting wands will be
  used to spot check players who have exited bathrooms.

http://www.chesstour.com/devices.htm

user4418: "Yes" is the answer according to FIDE.
They have published their Anti Cheating Guidelines which highlight the section of the new laws regarding this:

11.3.b. During play, a player is forbidden to have a mobile phone and/or other device capable of processing or transmitting chess
  analysis in the playing venue. If it is evident that a player brought
  such a device into the playing venue, he shall lose the game. The
  opponent shall win. The rules of a  competition may specify a
  different, less severe, penalty.

They also highlight the powers the arbiters and organizers have to enforce this rule:

The arbiter may require the player to allow his clothes, bags or other
  items to be inspected, in private. The arbiter or a person authorized
  by the arbiter shall inspect the player and shall be of the same
  gender as the player. If a player refuses to cooperate with these
  obligations, the arbiter shall take measures in accordance with
  Article 12.9.

Since amateur players often need their mobile phone on the way to the playing venue or on the way back to arrange lifts, etc, the commission amended the rules for amateur players as follows:

“In tournaments open to amateur players, the prohibition to introduce
  electronic devices in the playing venue may, and indeed should be
  waived. However, under no circumstances a player shall be allowed to
  carry a mobile phone or other device capable of processing or
  transmitting chess analysis, whether switched on or off, working or
  not, on his body during play. This includes, but is not limited to,
  carrying a device in a bag or in the pocket of a jacket. Any player
  found carrying such a device shall immediately be forfeited his game,
  with rating points calculated. A second offense during the same
  tournament shall imply an immediate ban from the tournament, with the
  player’s name forwarded to the ACC for further investigation.”

The net effect of this is that at our level we may take our mobile phones with us to the competition. They must be left switched off in a bag which may be by our feet when we are playing or alternatively left with the arbiter / organizer if they have made arrangements for this (some do, some don't). We may not take the mobile phone with us whether it is in a bag or not when we leave the board. If it is suspected that we have then the arbiter can request a search or pat down. Refusal results in the loss of the game.

8673: <p>A serious threat to human chess competition seems to be <a href="https://www.washingtonpost.com/news/morning-mix/wp/2015/04/14/chess-grandmaster-caught-using-iphone-to-cheat-during-international-tournament/" rel="noreferrer">phone-in-the-bathroom cheating</a>. Is anything being done to address this problem?</p>
 3757: <p>FIDE has proposed an Internet-based Game Screening Tool (see <a href="http://en.chessbase.com/post/fide-on-anti-cheating-plans-and-proposals-3" rel="nofollow">here</a> for more information) in order to identify possible cases of cheating by assessing how much computer-like a player has played.</p>
 12523: <p>The Continental Chess Association (USA) has the following rule for its biggest tournaments:</p>

<blockquote>
  <p>A table will usually be provided near the bathroom for players to
  temporarily check devices. If such a table is provided, players may
  not possess devices inside the bathroom. See rule 10 for penalties.
  Players whose games have finished and spectators are also not allowed
  to possess devices in bathrooms. Cellphone detecting wands will be
  used to spot check players who have exited bathrooms.</p>
</blockquote>

<p><a href="http://www.chesstour.com/devices.htm" rel="nofollow noreferrer">http://www.chesstour.com/devices.htm</a></p>
 4418: <p>"Yes" is the answer according to FIDE.</p>

<p>They have published their <a href="https://www.fide.com/FIDE/handbook/Anti%20Cheating%20Guidelines.pdf" rel="noreferrer">Anti Cheating Guidelines</a> which highlight the section of the new laws regarding this:</p>

<blockquote>
  <p>11.3.b. During play, a player is forbidden to have a mobile phone and/or other device capable of processing or transmitting chess
  analysis in the playing venue. If it is evident that a player brought
  such a device into the playing venue, he shall lose the game. The
  opponent shall win. The rules of a  competition may specify a
  different, less severe, penalty.</p>
</blockquote>

<p>They also highlight the powers the arbiters and organizers have to enforce this rule:</p>

<blockquote>
  <p>The arbiter may require the player to allow his clothes, bags or other
  items to be inspected, in private. The arbiter or a person authorized
  by the arbiter shall inspect the player and shall be of the same
  gender as the player. If a player refuses to cooperate with these
  obligations, the arbiter shall take measures in accordance with
  Article 12.9.</p>
</blockquote>

<p>Since amateur players often need their mobile phone on the way to the playing venue or on the way back to arrange lifts, etc, the commission amended the rules for amateur players as follows:</p>

<blockquote>
  <p>“In tournaments open to amateur players, the prohibition to introduce
  electronic devices in the playing venue may, and indeed should be
  waived. However, under no circumstances a player shall be allowed to
  carry a mobile phone or other device capable of processing or
  transmitting chess analysis, whether switched on or off, working or
  not, on his body during play. This includes, but is not limited to,
  carrying a device in a bag or in the pocket of a jacket. Any player
  found carrying such a device shall immediately be forfeited his game,
  with rating points calculated. A second offense during the same
  tournament shall imply an immediate ban from the tournament, with the
  player’s name forwarded to the ACC for further investigation.”</p>
</blockquote>

<p>The net effect of this is that at our level we may take our mobile phones with us to the competition. They must be left switched off in a bag which may be by our feet when we are playing or alternatively left with the arbiter / organizer if they have made arrangements for this (some do, some don't). We may not take the mobile phone with us whether it is in a bag or not when we leave the board. If it is suspected that we have then the arbiter can request a search or pat down. Refusal results in the loss of the game.</p>
