Wow, this is very new to me. I have never heard of a PTO paying for field trips. Our school district is responsible for that. We never give out blank checks. period.
We do business the same way; no blank checks. The teachers know how much they can spend without asking for additional fund that require the full organization to approve. This way they have to plan ahead.
Our PTO has been very successful in getting field trip sites to bill us. We usually send a letter from the board signed by the president, treasurer and principal to the destination site 4-6 weeks ahead and set up the arrangements. We're very prompt in paying and send a check out immediately upoon receiving the invoice. We're in the DC area and we have been able to work this payment schedule out with nearly everyone from the Baltimore Aquarium to the Kennedy Center and from the pumpkin patch to the Children's Museum.
Since our PTO pays for buses as well as admissions, we are billed for the bus at a later date. On the day of the trip there is a check waiting in the office for them made out to the place they are going and signed, once they take there count the principal fills in the amount.
in situations like this if we give a teacher a blank check they sign off saying they received a check with a limit amounted(maximum cost) and we require a receipt once they pay it.The principal works with us on this so her signature is right there so they know she is aware of them receiving the check. Other than that we do not give any blank checks to anyone.
"When you stop learning you stop growing."