By Avoid/ignore, I don't think that anyone here is suggesting that whenever that parent walks in, that you should walk out. What I meant by that was... Avoid/Ignore that parent when she is in one of her rants-or whatever you want to call it, but to otherwise be polite and not engage her/encourage her behavior. I wasn't suggesting that she should be given the cold shoulder and that you should be a complete snot. There is a difference between avoiding if at all possible while still being polite , as opposed to creating more drama by giving someone the cold shoulder. I thought that everyone understood the avoid/ignore manuever, I should have been more clear. When there is a drama mama (don't care where it's at..gym, workplace {assuming you're not management and are only an employee}, the shopping mall, whatever), engaging and their drama makes life much more difficult.
Gym is supposed to be a fun thing for your dd, and not be a stress factor for you - I would much rather enjoy my time watching/supporting dd and her teammates, not worry about if I was saying exactly the right thing so as not to offend someone and have a letter written about me. If that parent has issues (which she apparently has to many to voice, as she keeps writing letters) then the gym management, coaches should handle it. I'm wondering why this parent is constantly writing complaints instead of talking about whatever the problem is, are the coaches/management SO unapproachable that she can't just go to them? Or has she just complained so much that they're tired of listening?
By all means, if the issue involved you directly or your dd, then have a sit down with that parent and try to resolve it. ***I got the impression that none of this drama involves you personally and so by engaging the drama mama, you would be involving yourself where there is no need. I also (rightly or not) got the impression that this parent is in general not a nice person to be around - very negative most of the time - and that can suck the life out a person. By all means if that parent is otherwise the sweetest person in the lobby, then you make the decision as to whether to get involved with her or not. Just be careful to not get sucked into the line of fire, Life is too short to be caught up in someone else's drama/issues. Not being Superman, there is no need to try to "fix for a lack of a better word" everyone else's problems.