I’ve noticed it completely depends on the individual urchins personality, but I bet you don’t want to play “find the right urchin” either lol. At work I put our urchins in our frag tank and coral tanks to start, and if they turn into grabbers they get evicted to the invert tanks. We had a tuxedo urchin in the frag tank for almost 3 months and all he ever did was clean the frag plugs, never moved a single thing in there. Our halloween urchin was a monster and would go into the frag bin, steal ALL of the new un-plugged frags, and litter them throughout the tank. I had to scrape kenya trees off the glass for days.
Pics of the halloween attached