The people I know who go to burning man are incredibly thorough about picking up litter before they leave, and they wear the clothing at other events.

Roundtrip transportation to “the middle of nowhere” is no worse than rounddtrip transportation to somewhere. The only difference is that “somewhere” is sometimes accessible by train… but in the US, that’s only a small percentage of the country.

Ymmv, there are 70k people and there’s a lot of variation.