Ah, my hapless employer. CC's owned Intertan for a bit now and doesn't want to swap names: RadioShack sued to stop them from using their name, and CC fought it and lost several months ago. Last I heard CC told us they were fighting it, but apparently they plan to lose the appeal.
Given the status of both electronics chains in the minds of the public (at least from a red, white and blue point of view; hard to say how it is north of Minnesota) CC should be trying to sneak the Best Buy name in there somewhere.
Service plans have to be honored even if the company as a whole goes out of business. Usually a portion of the cost is placed into an insurance company to not only underwrite the cost of repairs or replacement for the store, but also to ensure that if the company isn't there to administer it that you get results.
Well out here the radio stations are too small too really accomplish those kinds of pranks. Now it all depends on what you're trying to accomplish with you prank. Admittedly not all of the ones I know are completely original, but I like them all.