DW and I would have been open to working with the PTA, but in our first contact with them, this happened:
PTA: "Come join the PTA! If you join and pay your dues today, you get a free t-shirt!"
Me: "Great. What is it you guys do?"
PTA: "Ummm... you get a free t-shirt!"
I would have gone running as well. I hate these kind of "free" t-shirts, particularly as I probably would never wear it.
Sadly not all PTA's are equal. The PTA at all my kids schools are very involved and do a lot for the students & teachers. They really work as a partnership with the administration & faculty. But I know this isn't always the case.