I had a female Gonodactylus chiragra that would crack open anything with a shell. When the smaller lighter prey items would fly away from her when she hit them she would retrieve them brace them against a rock and then proceed to crack them open. She was smart. Also she was kept in a nano reef with all kinds of corals she never touched and had tankmates including a Trimma Goby and a small cardinalfish that she didnt even pay attention to. Anything with a shell on the other hand was fair game.
Also I once personally contacted Dr. Roy Caldwell (one of the leading authorities on stomatopods) and I seem to recall him saying that he had only ever found one authenticated case of a stomatopod breaking a tank. I have had several species, some were in things as thin as a 2.5 gal nano or a small plastic aquarium, and never had one even come close to breaking the glass, even when burrowing or hitting the panes.
On that note I would like to hear from someone who has actually had one break a tank. Im not saying I dont believe your freind or your lfs employee's cousin's boyfriend, I just want to hear from someone with firsthand experience in this matter.
Ski