SIM-locking should be banned, period. Works well in many other countries. There is no valid reason to SIM-lock a phone, even for 60 days or 60 days of active paid service. It's a net loss to society as a whole. Even though I understand it can benefit Verizon in one case, it also prevented someone else to switch to Verizon from a competitor.
I think people in other countries generally buy their phones outright, rather than via provider payment plans, often at a discount, like in the U.S. and I think SIM locking is to prevent people from switching providers before those phones are paid off - and so the providers don't have to sue to recoup that money. That's probably reasonable, but doing it to just make it harder for people to switch is not. Of course, most phones smartphones probably aren't paid off after 60 days, unless providers have another avenue to recoup the money for the device, so I don't know how a policy works in that case.
From Cell Phone Unlocking:
Locked phones are often sold at a reduced price or as part of an installment plan. They remain locked until all the installments are paid, or for a certain period of time to ensure the phone is used on the network of the provider that sold the phone at a discount.
Even when paying full price for a cell phone, it may be locked for a short period of time, such as 60 days, to help prevent theft and certain types of fraud. Providers may have different unlocking policies for their prepaid and postpaid monthly service plans.
As for me, I bought my three successive cell phones over the last 26 years. unlocked and in full.