This is usually easily diffused by:
Option 1) staring at the guy and laughing openly at him.
Option 2) making them do an A-B comparison on the spot... Tell him if he can show you by just switching out some cables that it will sound $160 better then you'll buy them... Too lazy and no facility for it, so he'll most likely go away.
Option 3) looking them straight in the face and say you would never EVER consider spending a paltry $160 on cables and ask if he has any silver teflon coated cables with chicken fat.
Seriously, you gotta have some fun with these guys. Since we're in a world of mass market consumerism, there's no way you'll get these stores to change by refusing to shop there - there are simply too many stupid people out there who will fall for this stuff. that's why we still have:
It's a game - might as well have fun with it...