The Suunto pressure transmitter is notorious for releasing that special white smoke if the battery is put in backwards. Yes it is simple to design to protect this, at least for the transmitter, it isn't. If someone has a computer with a dead pressure transducer, it would be an "interesting" experiment
You'd have to be pretty cross-eyed to put the battery in upside down. I'm not even sure if it would fit in the housing if you tried.
Just to be clear. I don't have any reason to doubt your sincerity but are you speculating about this or have you actually seen this happen?
R..