Mistake nr1. - Trusting traffic providers here on DP who can say anything to sell their crap traffic source Their common phrases - ''100% adsense safe traffic''..... after this you contact and ask whats the traffic source - they say ''ts PTC traffic''.... ''but adsense 100% safe'' LOL 2. Placing yourself pages with Adsense to autosurfs and PTC (generating forced traffic) 3. Clicking your own ads or asking someone to click (when page gets suspiciously a lot of useless clicks)
Per day or month? I doubt this, I think they are starting to watch you if you have today 10$ and tomorrow 300$ to see the reason. And to reply to the topic I think is clicking your own ads. If you have adsense on a website with not eligible content they will disable the ads on that website and not ban the account or if you do minor mistakes. But if you really do not follow any rules, they will ban you.
Just read adsense tos perfectly and follow them if we get good organic traffic from search engines we will never get banned ....