One category of aircraft that almost *universally* uses pusher props is the autogyro.  Typically the engine is mounted in the centre of the craft, with the cockpit immediately forward, the rotor above, and the tail somehow mounted *behind* the prop - which requires an often spindly-looking strut wending its way past the propeller disc.

The same is true of some other types of ultralight aircraft, with a small engine often being strapped directly to the pilot's back, or possibly the back of his seat.  In most cases that's the only place it *can* be mounted without starting to build an actual fuselage.

In both cases, there is some sort of guard which would strike the ground before the propeller itself if sufficient pitch were attained, and the pitch required for this is much greater than most aircraft need at takeoff.  A propeller strike is therefore unlikely.