This is a brilliant idea!!
Beware not to click on ads in threads you have contributed to as Google are VERY quick to close down accounts - even if you have a load credit built up in your adsense account.
Being new to Adsense my bank account needed verifying, which Adsense do by sending a test deposit to the account that you've then got to tell them about.
Totally forgot about this, but happened to check my account for other reasons, and found a small deposit from Adsense in there. So have now successfully validated my account.
Don't forget to check YOUR account and validate too.