Yes and no: I recently checked a few online shops for Fairbuds and comparable earphones and for instance the German shop Cyberport states that the Fairbuds (and other earphones) are hygiene articles which cannot be returned if the packaging was opened. Since I’d really like to try such earphones I looked a bit further and it seems to be a common (and most probably legal) practice among online shops which is somehow understandable considering the effort they’d have in cleaning returned earphones and the customers’ desire to get clean earphones.