Even as an advocate of transparency, I'd still want to know why they want it and how it will be used. A financial report might be a far better choice.
The problem is 1) lack of clarity and 2) security
A bank of statement is data, not information. Until you put context around it the numbers are meaningless at best and misleading at worst. $10,000 sitting in the account? What does that mean? Plenty of funds? Or that you haven't yet recevied the bills from the yearly program and really there's only $3000 - and by the way, $2000 of that is allocated for projects already.
There's also concern on any document that displays account numbers. Having the account number is the first step towards identity theft or misuse.
Oh it's just for the principal? Sure, until he emails it out with his next newsletter.
You definitely don't want to appear to be hiding anything or reluctant to share honest information. But a genuine concern to be addressed is WHAT they want to know. Rarely would a bank statement alone answer questions.
I think the more important question is about the PTOs relationship with the school/principal and why they want the information. I supposed there's the legal/technical issue of if they have the "right", but practicality trumps that.
It's all well and good for a PTO to claim independence as a separate entity but the group and the school are integrally linked. The principal is a key stakeholder and sometimes the primary continuity from year to year. I can tell you from experiencing a PTO-related embezzlement that the PTO being a "separate" organization meant nothing. The school suffered most of the fallout and it was the school that people felt should have had more controls.
If a principal is worried about misuse of funds, he has the responsibility to investigate as a representative of the students. On the other hand, if you are facing an overly controlling principal trying to take over where he shouldn't, you probably aren't that wild about handing over information. Then again, as a group that has nothing to hide what does it matter who sees the financials? Or maybe it's just some sort of routine inquiry.
Also important is your structure. Is your organization an independent organization or are you operating informally as a committee of the school? Obviously if you are part of the school's umbrella, he would have the right to see/request anything.
Can you find out why the information is being requested? Frankly, the bank statements won't tell them much. If you know more about what they are after, you could find out if reports or other information would be a better choice for everyone.
I am curious...Our school secretary has asked for our PTO's bank account statements. At first thought, my reaction is YES, the statements must be needed for some reason. But as I continue to think about it, my answer is leaning towards NO. We are small, do not have much money, but we have been diligent with fundraising and successfully giving back to the school. Has anyone run into this dilemma?