I'd be for it as long as it wasn't monetary based ... or a monetary charge based on computer generated e-mails ... say flag an account that sends more than say 50 emails in a second, and charge that user a scaling amount based on how many emails were sent out per second. That'd pretty much keep legit home users, and businesses from having to pay anything, while spammers will finally get what they have coming to them. Of course, they could just modify their programs to send fewer e-mails per second to avoid the payment, which would result in them sending fewer spams.
I employed a "fight fire with fire" method, and started collecting the email addresses from the shitloads of spam I was getting. I'd check for spoofing and redirection, to make sure I was getting the right email address. And then I compiled some of this list on Lethal Death
We've gotten one of the fuckers to write us, demanding we take down his email address. He even tried claiming he was a lawyer, and was going to sue us for, get this "defimation of character" ... yes, he spelt defamation, defimation. And "persuit"
My thought is that one of his own spiders found his address on our site, and he ended up spamming himself because of it.
Fortunately ... or unfortunately, depending on how you look at it, we don't get any more spam, since I changed the default webmaster address, and also changed all the e-mail links to point to a form, so none of our addresses are on the site anymore.