I very much agree - probably one of the 'emergency' skills that is most likely to be needed at some point.The removal of the LP inflator hose followed by oral inflation is a fundamental skill that is actually rather likely to be needed during your diving career. . . . I've decided I am going to review it and make it part of any AOW class I teach.
On a recent week-long Bonaire trip, two divers in our group needed the skill (disconnect the LP inflator hose), and neither remembered it at the time. Fortunately, both divers were in shallow (10-15 feet) water when the inflator stuck, and neither was harmed by the subsequent buoyant ascent. One of the divers had been an OW student of mine, so I know we covered it in training. But, at the point when he needed to use the skill, he (said afterward he) just didn't think of it. That got me thinking - should I add that in to the recommended pre-dive safety check for AOW / other classes?
It is also one of the more difficult skills for OW students to perform, much less master. I spend more time with students on that skill, it seems, than on weight system remove / replace, regulator recovery, etc.
Thanks to the OP for posting this experience - it is a good reminder of the value of what may seem at the time to be a trivial exercise.