[Shop-talk] Modern throw out bearings

[Robert Nogueirao]

Folks forgive me for asking a question which is not shop related but I just can’t seem to get a straight answer anywhere else. Are modern throwout bearings  ( ball bearing not carbon block) designed to remain in no load contact with the pressure plate, that is, the bearing is always spinning? 
Just to b e clear, I too was taught to be sure to always allow clearance between the bearing and plate but does this apply to non adjustable direct action hydraulic clutches of today? 
Bob Nogueira