Your discussion group problem, argh. People who are deeply involved in good causes (or, in some cases, what they percieve as good causes) can have difficulty in understanding that there is a time and a place for everything, and that it's relatively easy to turn people off said good causes by provoking too much low-level resentment. I think making a general rule that states "discussion only" or some such is probably better than a rule saying "no fundraising", or something like that - that could be seen as too personal by your mother's friend and could cause even more disruption if she starts posting wounded complaints or perhaps hovers waiting for someone else to post even the most vaguely similar thing, so she can leap in fighting. (She hopefully isn't that sort of person, but you know, internet fights can be awfully seductive and can seem to have no RL consequence). "discussion only" is less personal and more positive - but will need quite stringent moderation for a while to ensure *everyone* is staying on topic.

I was on (not running) a mailing list once where a poster either would post either to ask for money for the IRA or to smugly report what percentage of their paycheque they'd donated. I finally privately mailed them and asked them not to post such things as it was deeply offensive to me to see foreigners trying to drum up support for terrorism in my country (I was polite! Conciliatory, even! This was the sort of list where ANYTHING offensive to ANYONE was supposed to at least be strongly thought about if someone said they were offended - and I'm talking on the level that if someone made a "who's 'we', white man?" response to an ethnocentric idiocy, there had to be several rounds seriously discussing the other person's claim to be purple, as well as the idiocy).

It did not go down well.