There's nothing special about + as far as email in general is concerned, that's just a convention some mail servers (such as gmail) use. Any server using qmail, for example, uses '-' for the same purpose, but + can be part of a full name there.
While cutting out the + might still get your mail to gmail users, there's no guarantee it would for anyone else. I don't really think the people doing the spamming care, and they'd rather it arrive in an account at all than burn their sources.
While cutting out the + might still get your mail to gmail users, there's no guarantee it would for anyone else. I don't really think the people doing the spamming care, and they'd rather it arrive in an account at all than burn their sources.