I love Yosemite... but can you really imagine driving there just to take cosplay pictures? And hiking in costume, or packing the costumes and changing at the top of the trail.... no @_@ lol. at least not for most of us.
And could people manage to not litter all over that beautiful national park? Not to mention that unlike Julian, you have a high chance of encountering a bear...
but hey, less yellow jackets!
~Kenshin no Miko~