Indeed. Google/Gmail do two strange things: a) While they support the age old username+whatever@gmail.com in order for users to hand out special addresses to mailinglists etc (eg: user+facebook@gmail.com, user+lkml@facebook.com) -- they don't distinguish on dots in the username (so username == user.name == u.ser.name etc). And b) they don't offer other domains than gmail.com, which leads to strange things like smith1, smith79 etc.

As for there being "no recourse" -- apart from spam, that's just wrong. It's much faster to reply with a "This is not your Smith"-mail, than it is to write a "return to sender" on an envelope. Same thing for getting phone calls from a different timezone etc.

[ed: I do agree that it's a bit more difficult with people that don't know their own address -- still think it should be quicker to reach their contacts via email than via comparable means.]