heedm, I anticipated your response regarding the car door and would like to make the following amendment to the example. Suppose the car were in a .5g left turn (around the round-about), and the door had a spring on the hinge that JUST held it closed against the .5g force. With the example being the same otherwise, I think the man pressed against the door would still open it, and his enertia would have done the work.
The interesting thing about this modification, it that it presents a rather crude way of isolating and studying 2 different "forces" acting on the door. Those "forces" are the enertia of the door itself and its reaction to the centripetal force of the car turning, and the enertia of the man sitting in the back seat leaning against the door, both of which are "apparent" centrifugal forces.
That has lead me to contemplating "inertial" and "non-inertial" reference frames, free body diagrams, and "apparent" vs real forces. All of these appear related and it seems that these things are used by scientists to facilitate the breakdown and study of all the individual "forces" acting on moving objects under scrutiny. In other words they seem to provide isolated "perspectives" focused on the particular forces being examined, I think.
I generally understand "apparent forces" and the Coriolis effect, but I don't understand what seems to me to be a very lose use of the word "apparent". I'll have to cogitate on these things for a while and get back.
BTW, this particular thread and the debate contained within it has been great fun.