Right now, people on this forum are having preconceived notions of what X-Games fans (which hasn't been confirmed by ESPN itself that they will even be near the area) will do when they see a bunch of people attending an anime convention...I'm pretty sure most people, even drunk, will just do a double-take at the cosplay and continue on their way. If that wasn't the case, they would've never held Star Trek conventions in Vegas...
I grew up in Las Vegas, and there are many different events going on at the same time, with attendees to these different events more likely staying at the same hotel. For example, on the same week last December, there was the Rock 'n Roll Marathon, Michael Jackson Fan Fest, the National Finals Rodeo, and a NASCAR event all going on on the Strip. The only issue I heard about that week was runners getting sick on the night time marathon run (a good reason why most marathons are held in the morning and when you can run on empty stomach). The point of the story is that you can have a bunch of fans of what to some may be mutually exclusive things in the same place, and more likely than not there will be more socializing than harrassing.
I agree with FancyIndia. If you really think a group of people that you may never encounter will actually come and bother you, then maybe you should just do something else that weekend. Very rarely does anyone want to pick a fight. The only people who do are the ones who think they can win and feel they have something to prove.