I'm a teacher & I've been yawning all day, as have my students (Ramadan, hot country, we're all shattered).
Hand up in front of mouth, polite tired yawn, fine.
Ostentatious 'God I'm so bored' yawn - nope, that's a warning.
Same with deliberately playing to the gallery belching, farting, & chair tipping. It's annoying & distracting.
I was doing behaviour walk & removed a kid from a revision session last week who'd 'only yawned miss! I don't even know why Sir called you!'
Well, because actually you'd been twice spoken to about distracting the rest of the class with your fidgeting, before the cavernous & noisy yawn with pointed eye contact with all your mates to make them laugh, made Sir decide he'd had enough.
So no, I think a bit much to sanction an involuntary yawn (I'm yawning my head off typing this - suggestion!
), but there is a definite taking the piss yawn which any teacher sees all too often.
Possibly your tired dd did that sort? I've known my ds (I teach in his school) to be capable of similar when being a smart arse. Part of the teenage condition.