Yeah, this is a problem, but if schools want to solve this? Easiest way: Give the tour guides microphones.
I’ve now been on close to 50 college tours over the past several years, and that’s the best way to get the parents to be willing to fall back—otherwise they (and I’ll be fully honest here, I) feel like they’re going to miss something they’d like to hear.
(Or train your tour guides to project. The single best tour I’ve ever been on for kids up front, parents in back? Colgate, with a tour guide who knew how to project their voice to fill a space, even outdoors.)