hehe! I know that feeling... you hear a customer ask a question (that you know the answer too) and the sales assistant's eyes glaze over and says "I'll just ask someone" They walk over to a likewise clueless manager and come up with some junk just to sound like they know. A simple "sorry, we don't know" would be much better (and appreciated in the long run)
Some decent basic training for the job by the company wouldn't go astray! Car Salesmen are a classic... (typically.. not all of course) They can get the brochure out to work out whether a car is front or rear wheel drive or how many cylinder engine it's got!