As I'm the one who made this statement - let me clarify it.
First, the ban is not automatic.
Secondly, it's often 5 strikes regarding ads that are trying to get around trademarks.
Third, it's often less strikes for more nefarious items.
Fourth, the 'five strike adwords rule' or '3 strike google kill' is what it's called in adwords circles. The 3 and 5 strike items are what people commonly see before they are either warned that their account will be shut down, or before there accounts are just shut down.
These rules are not Google policy.
Lastly, if you are a legitimate business going about your daily routine, who is not opening multiple accounts, constantly trying to use trademarked keywords in usual ways (iP0D, iPot, i-Pod, or lpod anyone?), and aren't thinking about how to get away with things - then the vast majority of times you won't have any issues at all.
And yes, there have been customers who have been let back in again; but usually with restrictions.