A year or two ago I used Google Checkout for an online product which sold a few hundred dollars worth. I got a couple of emails from Google saying to "Make sure to ship the products" or something like that. Since they were virtual goods, I didn't bother to go to Google Checkout and click "Shipped" or whatever.
Fast forward about a year, and I log in to Google Checkout to a message that says "Your account has been closed. We can't tell you why. There is no appeal".
The funniest part was I was trying to BUY something with Google Checkout.
I think it's bad practice to not tell someone why their account was closed. I understand if it was because I never clicked "Shipped" or whatever, but I don't even know if that's the reason.
Luckily there are alternatives to Google Checkout. I just wish Google treated their customers nicer. Especially because myself and my company spend over six figures a year on AdWords.