This is all very well as long as you're quite prepared to politely tell someone what they are doing is unacceptable. Because otherwise, how else would new people know? If you're rude about it you're just propagating an unwelcoming atmosphere which will just make the tradition die out if left unchecked.

There's a balance to be had. Remember they're not doing it to piss you off but because they're enjoying your music and want to "help out", however misguided it might be!