I feel for you!
Luckily, we're just starting out, so lessons like this are VERY helpful (at least
something good came out of it!). Right now we're dealing with some "queens" in our main office, and I'm at a loss on how to handle them. They've been there since the invention of sliced bread, and
love telling anyone who'll listen that. What a spot for you to be in! Give in and you hate yourself and worry you're setting a bad precedent ("well
she didn't have to fill out a request form...."), stick to your guns and you're "that PTO bi***" and will never be able to redeem your good name).
Maybe, without mentioning any names, send a flyer to each teacher saying something like, "We've had several(say it was just one and everyone will know who you're talking about), recent incidents concerning reimbursements to staff/administration for supplies where the necessary paperwork was not submitted prior to the purchases being made. We all know what a pain paperwork can be, and it's easy to forget to do. Please understand that when the PTO has procedures set in place it's not to make things difficult, but to protect ALL parties involved. We are a tax-exempt organization, and every penny must be accounted for when we file with the IRS. (And as JHB pointed out, putting the blame on an auditor/accountant can come in handy), Our auditor (or accountant, or whatever you use) has informed me that no further disbursements can be made without the proper forms being submitted.
Going on to explain the procedures would probably come next, then blah blah THANK YOU
SO MUCH FOR YOUR COOPERATION! My first instinct is always the less diplomatic and straight to the point, because one thing I detest is BS. I've learned the hard way though, especially in a small community, that that is a quick ticket to social purgatory.
Good Luck! Take strength in knowing others feel your pain!