Well, that’s nice that you can take the train to DC, but kids from the west fly and it costs a lot. My daughter didn’t go in 8th grade because it cost $2000. It did cause a social issue for her as most of her friends did go, and then they had a lifetime of ‘inside’ jokes and stories. I think they learned very little about Washington DC.
My sister took her kids on their DC trip and while it was a little cheaper (maybe $1000), the small private school did fundraising for a year, but it was mostly parents buying Christmas trees and wrapping paper so the cost was still on them, just in other ways. It’s not on the application who paid for the trip, but I’d guess most AO just assume the parents paid.