That's the main reason I don't have a paid signature. It increases your probability of being banned significantly!
I dont think thats true. The signature does not the ban make, the post quality is what does it. The correlation is between signature advertisers and low post quality, not so much bans to signature advertisers. While having a big flashy advertisement does make your spam stick out more to moderators, if you aren't spamming then it doesn't matter.
Actually I think that you're wrong this time. I actually had a screenshot of some staff member saying something alike. Anyhow, when you post a lot without a signature you get eventually noticed and if it is really bad you get banned.
Now, if you have a signature you're like a target. We rarely see someone get banned for making 15 posts a day (decent ones) without a signature do we?