Exactly. Someone who's going to steal, say, a dress, is someone who's at the comp anyway, knows its value, and how to sell it for a profit. But an entry fee is going to significantly reduce the type of thieves who are looking for an easy grab of a wallet, camera, cell phone, etc. Allowing anyone who wanders by (in a hotel, where the majority of NDCA events are, that can be a LOT of people) to move in and out freely means it's now completely worth a casual thief's while to pop in. The average person who goes into a pro-am event is a competitor (not likely to be committing petty theft, especially considering what they already spent to be there before you even bring in tickets), the pros, vendors, officials, and spectators who are usually friends or family of one of the above. Now, SOMEONE among that group MIGHT decide to snatch a handbag or an iPad, but it's a lot less likely than a total stranger wandering in because hey, door's open. And just having tickets/passes mean you've generally got someone sitting at the door watching who comes and goes--not memorizing, but a least there's some sort of observation. Let people wander in and out at will and stuff is going to walk away.