I agree with TA-t3...

The IMEI block system is very important in the fight against mobile crime. Circumvention of that system is irresponsible and doesn't really give you much in the way of anonymity, specially if you want to keep an identifiable phone number.

If you buy a stolen phone then it's your lookout. If the situation with phone sales in your country is that bad then insist you get to try the phone with your SIM card first to check it.

I'm very sympathetic to the Big Brother arguments when it comes to DNA databases and CCTV, but not in this case.