Yes, and some carriers do. Some will have a list of "supported devices", and if you try to use anything not on the list it'll be blocked. This isn't legal in

Yes, and some carriers do. Some will have a list of "supported devices", and if you try to use anything not on the list it'll be blocked. This isn't legal in some countries though. The UK telecoms regulator (Ofcom) prohibits any form of restriction on putting SIMs into devices, for example. Previously carriers would do things like saying that a SIM on a plan for phones couldn't be used in a tablet. A physical SIM or eSIM doesn't make a lot of difference with this, although a carrier obviously can't do anything to stop you moving a physical SIM between device. Changing an eSIM often requires contact with the carrier, so that's an opportunity for them to say no/make it difficult/charge a fee.