Dude,
The issue isn't whether you give it out or not.
There are also autoguesser bots out there, and I have collected MANY of their signatures from mail servers.
Things are at the point where the spammers are firing multiple random letter combinations at mail servers hoping something sticks.
It's not whether you give it out or not. We all have "waste" accounts we use

.
It just matters if your site is blocking a few major lists, usually SpamCop Blacklist and SPEWS.