Recently I've had a run of phone spam from people promoting charity raffles. The 'charity' connection is somewhat tenuous - I believe less than half the money actually makes it to the charity - but it does let them evade the Australian Do Not Call register requirements, which have a blanket exception for charities.
According to Sue Dunlevy, the Spastic Centre who called today are one of the worst offenders. A family friend has a child with cerebral palsy so I sympathise with their work but annoying people on an industrial scale is a stupid way to raise funds. More to the point, while this law stands in Australia you shouldn't ever buy a charity raffle ticket, unless you want to get onto a spam list from which there is no escape.
(The lovely Spastic Centre representative hung up when I started to ask about this, and the regulation says they're not required to disclose details or remove your name. I used to be polite; now I think I'll just hang up.)
Another problem with this whole concept is that raffle tickets are not tax deductible. So not only is this annoying telemarketer getting a hefty chunk of the bill, but so is the tax office. (Or rather, if you made a regular donation you'd get a tax refund which you could either also donate, or keep for yourself.)
I think the rational thing is: hang up on these callers, don't buy raffle tickets, set a fraction of your spending that you think is reasonable to donate, and do that as a lump sum in June so that you will get a tax deduction soon afterwards.