It seems like such a severe and drastic measure to refuse to pay the closer because the borrower was not able to provide a copy of their ID. But that is exactly what some companies threaten to do. This was in the instructions for the closing I did recently:

It's not our fault if we tell the borrower to provide a copy of their ID and they forget to do it. Or they live in an area where there are no copy facilities.
The notary signing agent spends a lot of time and money printing out the loan documents, driving to the closing, conducting the closing, dropping off the loan documents, and taking care of other matters related to the closing. And just because there is not a copy of the borrower's ID, the company is not going to pay for all of that work.
It's hard to say if this company would seriously withhold payment. And fortunately I have never been in a position where a company refused to pay me because there wasn't a copy of the borrower's ID included with the loan package.
Why?
Because if the borrower can't provide a copy of their ID, I'll provide one for them.
How?
I never take any chances. I always bring my digital camera with me to a closing. Yes, the borrower will say that they have a scanner in their home, and that they can make a copy. When you get there the borrower tries to make a copy, only to find out that they ran out of ink. (This really happened at a closing.)
'No problem. I'll run out to my car and get my digital camera.'
Good luck.
For information on how to make a photo of the borrower's ID with a digital camera, see:
Getting a copy of the borrower's ID with a digital camera
In a HUD closing I had a title officer refuse to notarize the closing documents because one of the borrowers did NOT have an AMERICAN PHOTO ID. We had to jump through alot of hoops and get a Real Estate attorney to do a Durable Power of Attorney deed specific for the spouse to sign etc before we could close that deal.
Now, I advise ALL my borrowers, you need an AMERICAN PHOTO ID to go to closing.