I think the public take a pretty pragmatic view on this and don't care as long as they are not losing money on it. A few years ago it was estimated that 3% or so of the 1 pound coins in the UK were fake (there is now a more secure coin type); AFAIK the quality was pretty good, so they weren't glaringly obvious, and it seems no-one really cared - if the supermarket or pub would accept it, then it's effectively money, right?