No, you would certainly NOT be better off creating new accounts. Can you not understand that posts by a senior member, who may be known by many users, carry more weight and generate more views than someone who registered 2 minutes ago?
Sig campaigns? HAhaaaaaa you really believe someone is mass buying shill accounts at .25 bitcoin each for a sig campaign.

that's cute.
Buying/selling accounts isn't against the rules but unsolicited PM spam is. You can report these type of messages and they'll get dealt with pretty fast. And how do you know they're to be used for 'propaganda' purposes? You'd be better off just creating a new account for that. Accounts are usually purchased for sig campaigns.