Sort of. It makes a deal with someone, and if it's still actively fulfilling its side of the bargain, then we can't take it, and it can't strike a new bargain.

[Which is probably the simplest way to think of it.]

So let's say someone says they want to live forever. As long as the orb is busy keeping that person alive, it's stuck with them.

Though I think they tend to like it that way.