We can't return cosmetics that we've tried over here, so using testers is kind of essential given the price of this stuff, I can't afford to pay out for something I'll never wear. That said, I usually just test on my arm, and I'll only try stuff on my lips (never gloss) - after watching it be sanitized - if it's a colour totally different to anything I've tried before, or something I'm really unsure of.
even MAC? I thought that was their policy for all stores
Even Mac. This is what the returns policy says:
Quote: We cannot accept returned goods that we reasonably believe have been used. In such circumstances, we will notify you that no refund will be available and you will be responsible for arranging for such goods to be returned to you within 28 days of our notification