I actually think it's the other way around. That chairs have a built-in function that makes them snap to tables and desks. Stools for instance has a so-called 'joint' that does the snapping. If you forget to attach your mesh to the joint, the stool won't move.
Interesting, so the desks have no joints at all? I have to take a look at the desks, stools, and chairs and compare all the "jointings" and such.
My cribs are live!