system
A chat on subreddit /r/wallstreetbets
human
Well let's think for a minute.. if everyone jumps in to use free trading, there would be liquidity and then If the market drops, those who jumped on trying to use free trades with the big boys would be scared and sell at a loss.  
  
 As ridiculous as that sounds, that is one example..

gpt
Free trading means people will be dollar cost averaging more