Yes, I remember Jon telling me about the guy sticking the clam in his pocket. But that is just wrong whoever put the bleach or whatever in the tanks at that store.
He suggested that only someone with training and knowledge of fish and the conditions they need to survive would be able to pull off the job.
It doesn't take any type of special training or knowledge to sneak some bleach in a fast food cup into the store and when the employees have their backs turned, dump the cup into a tank.
We had one of the two LFSs in town do something similar. Faked a break-in, and claimed all these expensive corals were stolen. Turns out it was staged.