To be honest, it's some of the atittudes here that really get my back up. Flying Onion, seeker and others make me think that it's not really worth it because they have some self-righteous belief that other people should, as a matter of course, support scout or similar activities 'or not complain when there are no boats to sail in or poorer children can't join'. 
Joan... your last post about private school kids - what about the bursary kids? How are they any different from other children whose parents can't afford activities?
It's about priorities; life-saving charities are going to take priority with me, they always will. Ditto for the Poppy Appeal. Most of us have kids and many of us have to priorise our spending, particularly now. Parents are expected to make sacrifices - mortgage, utilities, council tax, other bills, eating, clothing - hobbies and activities, alcohol, tobacco, Sky... parents decide once the essentials are paid - their kids, their choice.
Perhaps kids can't go on every trip they want to and perhaps they can't take part in multiple activities just because their peers do. They're still luckier than a heck of a lot of other kids and the self-entitled, bucket-rattling, lecturing posters are probably a big part of the reason why supermarkets are restricting them.
The arrogance of some who expect, as a matter of course, that others should contribute to their fundraising, or be referred to as mean, curmudgeonly or whatever, are doing their cause no favours at all.
Waitrose customers have the opportunity to contribute to local charities also, they use green counters, given at the checkout, customers choose which of three schemes to donate their counter to. No bag packers, no pressure and no snarky comments.