> That's simply not true. If it were, then carriers would never have bothered with the administrative overhead of locking phones in the first place. People do respond differently to economic incentives like whether their phone will turn into a brick or not -- that's Econ 101.

Well its not like they have to individually lock each phone they sell by hand and your phone does not turn into a brick if its locked to a carrier. Yes definitely the functionality is drastically reduced but there are also people/services that will unlock your phone for you that don't work for the carrier. Maybe if the phone actually was unable to be used at all if it was locked and you didn't pay the bill, that would be a valid argument.

I can't really agree with just because they do it, it must work argument, I have, and I'm sure you have too, worked for a lot of companies that had policies or practices that did not work.

I worked in customer service for Rogers, a large telecom in Canada before unlocking was mandated. There were lots of customers that did not pay their phone bill despite their phone being locked. If people don't have the money (whether it be their fault or not) they aren't going to pay their phone bill no matter what sort of incentive you give them.