When I was an undergraduate, a lot of my field classes involved being marched around and the lecturer pointing at things and tell us what they were.
It was almost like a lecture but outdoors with a big stream of students charging after this individual who they could not hear anyway. Now my experience of fieldtrips (from talking with colleagues across multiple institutions) is that they are much more experiential learning. This has meant that fieldtrips have become more accessible as students have more time to process things and the small group nature of the work means all the student can hear each other/the facilitator. Setting up experiential tasks also means colleagues are more likely to consider accessibility and inclusivity issues during the planning phase.