"No handphones should ring during class" Wait, did I say "ring"? I must rephrase...
I always make this announcement on the first and second lectures (yes, I repeat myself at least once, for the benefit of those who skip the first lecture). I realised my error, when once, within half an hour after my announcement, a guy's phone went "hahahahah". It managed to stop me in mid-sentence. OK, technically, he didn't break my rule, because my rule was that phones were not allowed to ring - I didn't mention anything about whether they were allowed to "laugh".
Hmmm... I would have to evolve to match the modern phones that can make all sorts of tones, wouldn't I?
There then, for the many following semesters, I rephrased my announcement to "No handphones should ring or laugh or sing during class" That had worked all right for some time.
This semester, during a lab session, someone's phone burst out shouting "I want to f*ck you", and the unashamed owner actually allowed the phone to be vulgar several times before taking the call. The class seemed to enjoy the "fun", but I (maybe being too old) failed to see anything funny. And just today, during lab session (again!), while the students were being tortured by an exercise which they had to complete and submit by the end of the class, someone's phone actually chanted a couple of verses of Buddhist scripture - the kind you'd hear in temples or at ppl's funerals... I don't know which. (Gosh... the exercise was that tough?)
So there - time to rephrase again: "No handphones should ring or laugh or sing or curse or chant, during class"