Perhaps she may not even be aware of what she is doing. I personally appreciate it when someone comes to me about a problem they have with me.
Taking her aside and explaining, try to be very tactful and non-accusatory to get a positive result.
For example, I really appreciate it when you do...I think it would be even better if you could do...
Why not lead by example. When she behaves this way, simply say "Oh, when Suzy does that it drives me crazy too. We started taking away her favorite toy(or some other non-violent discipline method) and she shaped right up. We did that because when we yell at her, she just shuts down and doesn't hear what we're saying." It doesn't sound like you're telling her what to do and maybe she just doesn't know any other method. However, I have to wonder about someone who would be verbally abusive in front of other people--what do they do in the privacy of their home?
If her behavior continues, I think you have no other course of action than to speak privately with her about it. Do you really want to listen to her rant and rave? Do you want your children exposed to this? What if she decides to discipline other misbehaving children at some event?
First maybe address child care at meetings. If there is none, then kids shouldn't be there. If child care is available during meetings, then the kids need to stay in an area away from the meeting.
Is anyone friends with this person outside of PTO? If so then that person probably has a better chance of getting through to this person. If not - then perhaps someone could take this parent aside (not in public, not with her kids around) and perhaps say that "it was brought to our attention" or "we had someone explain that ______ (behavior) made them uncomfortable".
This sounds so immature and selfish but I'm going to put it out there anyway. We have a board member (not executive board) that is very negative and let's call it unprofessional. This is a very delicate situation because we need all the help we can get and wouldn't dream of turning away volunteers so my question is...how do you tell an adult that her behavior is inappropriate without making the situation worse? I don't want to give specific examples in case she reads this board...but one example is her disciplining her child in an almost (verbally) abusive way in front of other parents at a PTO/school function. Help!!! :confused: