Probably pertains more to FW fish than SW since I heard this at Walmart but im sure there are LFS out there with security scanners too. The employees at Walmart always tell people when they are buying fish to hold the bags up over the antitheft scanners when going out the door or it kills the fish. I've heard this before and it was brought up recently while talking to someone with a FW tank. They said that they bought several fish from Walmart and they were all dead the next day because they carried them through the scanner. I call bull but I really don't know. If the scanner kills fish I really don't want to walk through there either!