Yes, and when it breakes on the engine at a high RPM, which is where the centrifugal force is, well, it happens quite quickly and can do some damage if something is nearby or in the path of direction that the prop takes when it breaks.

Oddly enough, this is one check that I do kind of automatically, without thinking about it. My instructor, a devout pattern guy, taught that to me when I had my trainer. It was a good time to learn this practice because that's when we break the most props.. during training. We break them for various reasons, usually hitting the ground with them with our sloppy landings, but when replacing the broken prop with one from our "prop wall" that is under development at the time, well, grabbing one out of the box, and flexing it just as you suggested sort of came automatically after a while. If fact, when I buy a prop, I usually buy two of the same size and test them at that time, unless I mail order them, that is.

Good point, Highplanes

CGr.