Gary Drescher wrote:

I've never felt worried about someone landing on me while I'm holding in
position at a controlled airport, but perhaps the risk is more significant
than I'm aware. Have many such collisions actually occurred?

I never have either. The controllers at Syracuse would always tell me of
the inbound aircraft's position ("Bonanza XXX, position and hold, regional
jet 5 miles out") and tell the inbound aircraft about my aircraft entering
the runway for a P&H ("American Eagle XXX, cleared to land rwy 28, Bonanza
going into position now, will be departing before you arrive").

In these examples it is obvious that the controller is completely on top of
the work load, unlike a few of the recent incidents that led to this
decision by the FAA.

In the tight P&Hs (an aircraft on a three mile final) I do always think of
the scenario of how all involved would handle my aborted takeoff, should it
be needed.

--
Peter