I do it all the time, and not just to friends, but to group brew days like "Teach a Friend to Brew Day" or the AHA Big brew. We get about 50 folks brewing on those days, ALL bringing their gear. Some people bring trailers hauling herms and rims systems even.
We usually have a tent of homebrewtalkers.
A lot of us from HBT get together quite regularly and brew together. I've lived the last decade in lofts or condos with no yardspace, so if I want to do full volume brews I almost always have to haul my gear somewhere.
There's no problem with transporting your fermenter, as long as you make sure it won't spill. Otherwise the agitation is just a form of adding oxygen to the wort.
It's not really a big deal. I think it's part of the fun of brewing is getting a group together to brew, and that requires folks to haul their gear someplace.