It makes total sense, it was just not something I ever experienced. But I do remember in our first class, standing outside of the fence when one dog was running, but after like 3 classes, the trainer decided we and the dogs were all fine to be leashed in there, and never had any problems. 2nd trainer was the most professional I had, and she competed with her BCs, and has a well known training club around here, and she never asked us to crate dogs either. Current class is during the day and there is only 3 dogs (2 little, 1 aussie) and they're all fine together.
It's funny though, I'm not really in the 'dog world' per say like some are, since I don't really do any competing, and such, so when I went to the Barn Hunt trial a few weeks back, it was funny to me to see everyone's dogs in crates in the back of their trucks and cars. Jackson, being my only dog, and my traveling companion like almost everywhere I go is just so used to... being with me. I could never leave him in a crate in my car LOL and I know it's not cruel by any means, it's just not what he nor I are used to. The most I do is leave him in my car if I run into the post office, or Chipotle or Walgreens or something hahaha.
I know I would have no issue training him to be in a crate if I had to, it's just not something I ever cared to train. In our family, dogs are only crated for a short time as pups, and have just always been left loose. So it's just kind of foreign to me. LOL