i think chess.com gives so many smothered mates in their tactics trainer so at least one of us might get a chance to execute it one day and show everyone else in the forums and say "you see? it is possible"
They do happen. And like the man said, there is plenty of practice on TT. I have had about three in my life.
But, I have never had to do a K, Kt, B vs K ending, in spiite of the fact that I took the trouble to learn it. But, unless you do things regularly, you can get out of practice.
did you ever do a smothered mate?