I've purchased my fair share of stuff from Best Buy, but only for convenience and only when I already knew what I wanted. A year or so ago I had to return a malfunctioning video game player, and while they took it back, it was a headache and tedious. For electronics stuff, I now use a different store that has better service. They are what they are and their lousy service translates into cheaper products, for better or worse.
I probably would have taken the chance with the panniers from BB if they were something I was already planning to purchase, but this does show you that there are risks involved. Now days, anytime you have to deal with a large organization where something has gone wrong, it's likely to be a giant headache. Most places have all kinds of automated systems, and fortunately they usually work, but when something goes haywire, then it's sometimes impossible to get an intelligent person with decision making ability on the phone.