Yeah, if you ignore the corollary #shadybusinesshack, which is to strip + suffixes from @gmail.com addresses, or any other domain with gmail MX records.

Slightly more advanced trick is exploiting the fact that Gmail ignores . in addresses, so that [email protected], firstlast, fi.rst.la.st, firstlast.., are almost infinitely unique encodings of the same mailbox. But again, smart spammers can just remove all dots so that the spammee can't tell who sold the address.