Something I'm curious about: we teach pitot tube/drain hole blockage scenarios all the time, but what is more likely to actually happen? Is it more likely that just the pitot tube will block and the drain hole will stay open? Only thought of that since the drain hole is on the underside of the mast, and is not making direct contact with whatever could block it up (icing, bugs, etc).

Just seems very unlikely that both the pitot and drain hole will both block, since they're in complete different places.