Go for it as long as they stop! The sheltland I used to ride had no breaks, so when I galloped him out bareback I could only turn him and he would eventually stop. I also use to gallop out my 14h pony that absolutely loved to gallop. He was dead easy to stop though.i took him over a 2ft log out and did it better then in the feild :) I still ride out now and then bareback on my mare that can be scatty. I find it easier to stay on her bareback sometimes rather then with a saddle on :) i'm like you, I prefer hacking then schooling.
I used to gallop my OTTB with just a halter in a big pasture ...
Ahh those were fun days even thou they were just last summer!! Lol
I don't really ride anymore right now due to back problems and chronic pain