SpamAssassin doesn't bounce email. It tags or deletes it.
But have you noticed that everyone moans about Spam but few bother to go to a ISP that provides Spam filtering as standard or to cough up a few quid a year to get a email address that's is filtered.
Me thinks a computer seller could make a mint by promoting that they're selling a computer with Spam filtering built in.
I don't think any of the big resellers do this yet and its abuig issue with every computer user too.