an important tool used by cellular carriers to prevent customers from jumping ship.
Handset locks don't stop anything, it is contract law which ensures people pay for the remainder of their contract terms... Handset locks just decrease the usefulness and resale value of the handset, while creating an artificial grey market in unlocking methods.
I intentionally avoid any operator who supplies locked handsets.
The purpose of locked phones isn't to keep people from switching carriers. Having similar plan pricing, focusing on "best coverage" in specific areas, employer discount programs, retention offers, different network technology and most importantly individuals own reluctance to change does that.
Lots of people want to believe that the big companies lock phones to trap them but the real reason is fraud. Cell phone fraud is a lot bigger than most people think.
It works like this: Company A sells phones and service for Verizon. Company A buys Iphone 6's for about $600. A person comes in and buys 2 iphones for $150 each totaling $300 with a contract. The person then goes to another location to buy more phones. As many as they can get away with. Then the person never pays their bill so Company A NEVER GETS PAID BY VERIZON. Thus they lose $600 per phone. 2 phone = $1200 loss, 5 phones = $3000.
It used to be that people doing this would focus on AT&T. Now they just want Verizon phones because they are unlocked for international use. That makes it lot easier to resell them overseas.
I'm just glad that things are moving to installment plans/ full price phones. Now the carrier is the one taking on the liability. And since installment plans require a higher level credit check it's a lot more difficult to commit fraud. Of course, what it means now is that those with poor credit (mostly low income) are now stuck with cheap phones. They come in to get a good phones and now they have to make a 30-40% down payment, if they can get them at all. It use to be that they would just buy last years flagship phones on contract for $0-$50.