Moves to control ambush marketing at events have been met with mixed reception: ambush marketing regulations enable the event organizer to prevent competitors from impeding on a company's exclusive rights to serve as an event's sponsor, thus making their sponsorship rights more lucrative. Laws enacted to control ambush advertising practices have proven to be controversial: critics have argued that ambush advertising regulations can inhibit free expression and prevent businesses (such as restaurants, sports bars, and pubs) from even mentioning an event, and that a country's existing trademark laws can be sufficient to protect organizers' intellectual property without granting them special powers.