I was sent an email today (which I think has been going around since 2009) about telemarketers going to have access to my mobile and it will cost me if I answer. This is a scam. The email is a viral email. To verify this you can check out this link
The link given in the email is a virus. Always sounds so plausible. My son tells me it's OK to register for 'Do Not Call' (it will take about 30 days to work) but you will then be put on a Charities list and you will still get them ringing.
You can read more on the link about this scam. You will not be charged if you answer your phone.
Hope this helps someone who hasn't heard about it.
I doubt that the act of registering with ACMA's "Do Not Call" will specifically put you on a charities list per se, but charities are exempt so if you're already on their "sucker list" they can continue to call.
I will never give any details to a charity that cold calls just in case they aren't who they purport to be.