I don't work in a bank (haven't since 2004), but can offer some thoughts --
1. Your PP agreement should spell out what you do when the customer hasn't acted by your deadline. Your PP agreement might say you require a "Pay" response for each item the customer approves, or it might say you will pay any item for which you haven't received a "Don't pay" response. I've had customers on both sides of the question -- some who wanted us to bounce everything without a confirming "Pay" and some who wanted us to pay everything except the ones they said "No" to. Usually the customers that routinely issued a lot of checks were in the latter camp.
2. It makes sense to start calling non-responding customers before the cutoff hour if they are new to the game. But for others, I think it only makes sense if a regularly on-time customer slips, and perhaps call at the deadline to see if something's wrong.
3. On the forgery question, it makes sense to get an affidavit if you return an item code L (signature irregular, suspected forgery) in case the check comes back again for payment. Then you can return it a second time code Z (forgery, affidavit available on request).
_________________________
John S. Burnett
BankersOnline.com
Fighting for Compliance since 1976
Bankers' Threads User #8