I asked google and they did not say anything about banning my account or suspending it. All they said was it can be a rumour to spoil its reputation or stumble upon's reputation.
Actually, the stumbleupon traffic does not result in clicks. Those visitors just glance at your site and move on. I doubt that those 75 clicks were the result of the traffic you received from SU. Check your stats and you might get the answer to your dilemma....
hi i stumble all my adsense site as they are made as well as many other sites.never had any problem with adsense over it .The sites get listed in googe then who knows who is making the clicks.Youll only ever get paid what adsense says your getting clicks or not
If you're concerned about it, or don't like the low CPC/eCPM, you could always use PHP (or another server-side code) to make the page not show AdSense whenever the referrer is SU.
Is Ad-sense really that dynamic that it can tell when you have a surge of traffic and it will limit your cpc? Very interesting. How does it distinguish? Gradual v instant?