In my opinion I feel that most lost rabbits will either be found by someone who thinks it's cute and wants to keep it or found by a fox. They cant look after themselves as well as a dog or cat
"Dyrebeskyttelsen" in Norway (kind of the Norwegian equivalent of RSPCA I guess) go out "hunting" rabbits occasionally
The rabbits they capture are taken care of until the owner is found or they get new homes.
Also I believe that most "decent" people who find a domestic rabbit would try and look for an owner, and if you at the same time put up wanted-posters, and said person sees it, most would give the rabbit back.
So yeah, some do try and capture runaway rabbits, not all are taken by foxes or stolen
Mine aren't chipped. Sasuke has a registration tattoo in his ear from NKF so I think he could be traced using that, Aroma hasn't gotten hers yet (they get the registration tattoo when they've gotten 93 points or more at a rabbit show, she's gotten 91 at most, during shedding) She's tattooed, but only in one ear and she can't be traced with it.
I would like to get them chipped, although I doubt many will look for a chip in them, at least for Zakura since she's not tattooed (not a show-rabbit)