I hate going into these places as I often overhear that sort of thing being told to their customers. It's not my place to convince people that they're being ripped off though, that's for themselves to realise unfortunately, as much as I've felt like intervening (I even work in a rival local shop), I'm not going to undermine their staff on their premises who are just doing their jobs, even if the company policy is push everything.
It's like this in all sorts of businesses. I'm sure there's some chaps right now getting told they need x, y, and z for their car that's just been serviced, and the garage is charging a small fortune for it, even when it's not strictly necessary.
It's up to the buyer to make an informed decision and realise that what they're being told by a SALESPERSON is not necessarily what they need. Working where I do, I never try to push sales, only be helpful, but then that business is just a small one, perhaps that's why. Still, I'd never expect a customer to flat out take my word for it without doing their own homework on an expensive purchase.
