telephone numbers going public, page-9

Tangrams, it was the bit about mobile numbers going public that got to me, which was why I checked it.

The charging bit is if you ring back a number and the call gets charged to you. That can happen, like with any phone number that charges back. eg that's how a lot of lotteries make their money, television shows with call back voting etc. I don't know if there's a way that an unsolicited call could be charged to you without your knowledge (eg with the old reverse call chargeback system you are asked if you'll accept the call and pay the charges before the call is put through).

Nothing wrong with the Do Not Call register - it's a great idea. (A silent number is a good tactic, too.)

It seems to be an unusual prank in that it's performing public good, not harm :D