The slogan emblazoned clothes are references to the campaign that was started when Katie was still married to Scientologist Tom Cruise - who she divorced in July - urging her to leave the actor.
Another member of the party was dressed as a young Tom from 'Top Gun', but when they spotted who was on the next table they covered up their T-shirts.
A source told the New York Post newspaper: "When they sat down, they exchanged an awkward glance with Katie, but she kept her cool and didn't say anything. The embarrassed Halloween crew quickly covered up the costumes before Suri got a chance to take a look."
It was recently claimed Katie is getting ready to date again following her separation from Tom, 50, and her dad Martin intends to help her find a new guy.