I have used Coral RX to dip 30 or more SPS frags and colonies after purchase and prior to introduction to DT
I have only had 1 mini colony dipped that resulted in live crabs being seen in the treatment vessel ( they where still alive but had vacated the coral)
I have several colonies that have been treated, that I have seen live crabs in the coral, after the coral was placed in the tank which naturally includes a couple (small green furry types that seemed to be creating a bald area on the coral) that I have had to later remove using a toothpick and tweezer combination to extract
if you have a crab you want to keep, IMO better to remove from the coral using toothpick/ tweezers etc to pursue it out of the branches where you can eventually flick it into a waiting collection vessel