I decided on whim to try AdWords for a couple of clickbank products. Apparently one of them was against the TOS though I was not aware of it at the time. I haven't read the TOS but since both of my ads where approved I figured everything was OK. I run these two ads for 4 hours and shut them down. One of the ads got maybe 2 clicks and couple of dozen impressions, the second ad had no impressions and no clicks. I paused the campaign after 4 hours. A year and a half later I receive an email from Adwords notifying me that my account has been suspended for running ads against the TOS.
Talking to support was like talking to a brick wall.
I am fairly certain that the only reason I got banned was because I left these ads on pause and didn't actually delete them. They probably run a scan at some point looking for ads that infringe the TOS and picked me up. It's entirely possible that these ads weren't against the TOS at the time I set up the campaign but well, it's Google so there is no one to talk to.
I didn't need to use AdWords since but I probably will at some point so it certainly sucks for me.