I have a question...they let their rabbits run loose, not in a fence, and they don't run off?
I would try to get a live animal trap from Lowe's (we have one, it was about $20. Bait it and catch the rabbit and take it to them and let them know you MEAN business. Maybe if they see their precious bunnies in a cage and in the hands of someone who's a bit ticked off, it will scare them into keeping them up.
