For my boy, the one who will bite me if i don't give him something else to munch on while in my arms, it's a straight out nope.
I rarely pick him up, even if it would be far easier to just do that rather than any other good method of moving him. Most rabbits don't like being picked up anyway while most moving cam be done by simply guiding rabbits on floors or into and out of carriers.
I know he wouldn't stay still long enough for me to put a harness on him safely, and there's no point in making them more stressed. Also, harnessing a rabbit isn't at all like a dog or even cats. Buns just have minds of their own and would rather alter between grazing, napping and dashing than go where you want them to go. A harness just isn't long enough if they suddenly decide to zoom 20 meters of your yard. If they were to get stuck in their harness, serious injury could occur and something could even dislocate or break.
Edit: i did try to take my girl outdoors once, but she had her post-spay vest on, so no need to hustle with the harness-on thing, and it was about the last day she had to wear that thing anyway. I tried attaching a rubber string to give it slack and she.... Just found herself a sweet shrub to munch on and didn't bother to move a single centimeter. My point being that rabbits know what's up and won't really want to move if somethi g is hindering them. They don't really appreciate a looming human holding their possible escape route either.
If you want to give your rabbit safe time outdoors, just get a portable xpen and you can hang out with them so that nothing else would be enticed to swoop in and take your pet as their treat.
