In Poland all phones have to be sold without a simlock. Doesn't matter if you are on contract or not. The world still hasn't collapsed, people on contracts continue to pay for them, nothing has changed.
Some contracts can be nastier (e.g. no early termination, just pay the rest), but that may just be an unrelated local difference (I've seen the same thing with residential ISP contracts, where there isn't a SIM-locking equivalent).