That's not true at all, and is a bad analogy. You own your house. If the bank has a mortgage, then they have a lien on the house. If they want to take possession of it, they have to go through a foreclosure proceeding. They can't just walk into your living room and start watching TV. Your house is real property, which has lots of strong protections. Comcast, on the other hand, does own the router that they lease to you, which is a chattel and therefore subject to a different set of rights. No, they can't walk in and just take it (that would violate your real property rights). But they do own the network, and if their contract with you is written in a way that permits them to reconfigure a leased router to grant somebody else access to their network over wireless signals that you're leaking out into the air anyway, then yeah, they can do that.