Trouble is, if you're employed by an organisation that has decided to get involved with any charity or "corporate social responsibility" wheeze, there is usually considerable pressure to give up your time to do whatever is required, with no recompense. Fine if you support the charity in question, but it's a bit annoying when it's (as in the case of one company I worked for) the charity of which the chief exec's wife just happens to be a trustee. Unless you're a stroppy bastard / very resilient, it's hard to say no.