They don't move very often, if at all. They are happy in their pvc end caps and they are reef safe. Most of them have been in the same caps for over 6 months or more. @yoyohead and @DaddyHook have had a few since March and just left them in the caps.
I moved mine to another tank and removed them from the caps. I do have one that is attached to the front panel. It occasionally will climb to the top and right back down to where it was.
I think it’s time to grab some more for the new 50 gallon!