In Fallout 3, we were told that we could not remove the PipBoy because of some biometric things. This is not exclusive to Vault 101, as in Operation Anchorage DLC, we saw a dead Gary with a missing arm and a saw, implying the BoS tried to take it from him.
And then, in New Vegas, Doc Mitchell gives us his own PipBoy, implying he managed to take it out.
In Fallout 4's E3 Conference, we see the player finding the PipBoy on a skeleton, and he just wears it using a simple "belt buckle" (https://www.youtube.com/watch?v=H86cZwjdGwU)
So... What about the PipBoy now? Can we, according to the lore, take it off that easily or not?