D&O insurance is basically legal defense insurance. You as an individual might not end up out of pocket for anything since you're incorporated, but the corporation is still going to have to pay legal fees to defend against a suit being brought. The D&O insurance will cover those legal fees.
I guess incorporation would protect the individuals, but what about the PTO and its assets? You wouldn't want a lawsuit at the beginning of the year to eat up all the PTO's funds so you couldn't fund the activities/field trips/etc.
mum24kids has a great point about reading through the exclusions. AON's can cover bounce houses, but only if the vendor lists the PTO as an "additional insured" on the vendor's policy.
Our school district requires that we at least have general liability insurance. And because you just never know, I would never go without the fidelity bond/crime insurance. I consider that a bargain. D&O coverage I go hot and cold on, but being the daughter of an insurance agent, I always buy it.
The additional accidental medical insurance requirement did bother me--it's pretty pricey. At the time I renewed our insurance, I didn't have a whole lot of time to do any comparison shopping. Next year, I'll be looking around some more.
There are at least three brokers out there dealing with parent groups of whom I am aware: AON (which is who PTOToday is now using), AIM, and RV Nuccio. They all offer similar products to PTOs.
One of the bigger problems with insurance, though, is I don't think people bother to read some of the documentation that comes with it. You might assume certain things are covered, and then find out that they are not. For example, we sponsor an afterschool sports club--but our policy excludes bodily injury due to participation in sports activities or contests. Having a fall carnival? Make sure your coverage doesn't exclude bounce houses before you go out and rent one. It's useless to spend the money on insurance and then not pay attention to what it does and doesn't cover.
Our PTO had some insurance from AIM, which was affiliated with PTO Today. PTO Today then started offering its own insurance (different carrier), and we switched, in part because AIM didn't bother to send us a renewal notice until after our previous insurance had expired.
This year, I'm still deciding what to do; PTO Today (or their carrier) decided that the package MUST include excess accident medical, which I didn't feel is necessary for our group, based on what I feel our liability exposure should be for our activities. You can't really pick your own insurance with PTO Today, you get coverages
X
X and Y
X, Y, and Z
but you can't get Z by itself.
Our PTO is fortunate in that we've never filed a claim. We originally did not have fraud insurance, but I added this -- and found some other parents to help with the monthly bank statement review and year-end audit. (I'm the treasurer, so I didn't get ruffled feathers thinking that the board didn't trust me.)
I was discussing coverage with other PTOs in our town; one of them had Property coverage, but I pointed out that our PTO doesn't actually own anything -- we donate money to the town/school committee, which makes the purchases.