Don't google have an alternate way of verifying the user's address. Maybe they could simply call up the user and verify his identity. Then take the address on the phone itself. If the user gives wrong address, he's the one who will lose the cheque money. Why send it via mail? I'm sure many of their verification PIN mails must be getting lost in the postal system.
Use adsense help or search function next time. https://www.google.com/adsense/supp...r=14836&ctx=en:search&query=pin&topic=&type=f
Oh Yes! I'm sure cheques are getting lost as well. I read on many forums, people asking google for help because they didn't receive their cheques.