Well, if you ask me, they didn't banned me. They first sent me email that one of my site is against adsense TOS and they have disabled the ads on that site. But if you are new to adsense or make only few bucks a day, then they will simply ban you. Hope this helps.
same goes with James, mine got first warning email. they only disable ads on that site. the rest of site, including account still ok. make sure your account is 6 months and up. mine is about 3 years already.
I agree, why wait for the warning or banning thing, we should do it safely at the start by complying with Google's policies.
A couple of years ago I noticed that there were no income being reported, so I checked my site and the were ads being loaded at all. I contacted google and they got back within twenty four hours and they told me that my account had been suspended due to ads being displayed on adult related pages. I have a directory and one of them is "adult services" with ads for some escort agencies and there were adsense being displayed on them. I tweaked the pages so that adsense ads were not being shown on the adult pages, emailed google and within another twenty four hours my ads were showing again.
No. They will restore you once you have corrected the situation or condition, unless you are a flamer!
They won't warn you, but just ban you. I got banned at 00.02 in the middle of the night... Sohorrible