This is rewarding bad behavior. The offspring should be conditioned to awaken themselves by having an unpleasant experience occur when they don't awaken when expected.
As long as it's a rare occurrence, I don't really see the problem here.
https://www.psychologytoday.com/us/blog/feeling-our-way/2014...
Nobody wants to avoid the behavior when punishment is introduced, they want to avoid the punishment itself. Typically speaking, this is done by circumventing the punishment, rather than correcting the behavior. Besides, (almost) nobody purposely sleeps through their final - especially not if they take the time to ask someone to be a backup alarm. You'd be advocating for punishment of an accident at that point, which is aggressively useless at best, and sadistic at worst.
Completely on this subject though, I find the behaviour in question here insane. Mostly because adults are supposed to be independent and competent. Of course, not everyone is raised equally. If this works for them, who are we to judge?