The art of subliminally controlling your students

A colleague of mine has been suggesting that he might open all of his lectures with a slide showing this picture:

 

This seems like a good idea.  After all, it cannot be doubted that a mobile phone ringing in the middle of a lecture or a seminary is a distraction.  It is worth having a subtle reminder to students about acceptable behaviour during a class.  This did make me wonder though - there is a whole language of signs which could be used here, and perhaps subliminally flashed up on the screen during the lecture in the kind of way which works so well for Darren Brown.

For example,  since it is equally distracting to have students on Facebook or tweeting your latest terrible joke during class, you could have:

And since there is always a good chance that I am having a bad hair day, I would personally like to have:

Of course nobody likes it when a student arrives to a post-lunchtime lecture with one of those awful polestyrene trays full of chips, so it would be remiss not to have:

A quick flash of:

would resolve that tinny whiny sound from the back row that can so infuriate - and while on the topic of bad behaviour on the back row perhaps this:

would not be a bad idea either.

That seems to pretty much cover all the bases - although just to ensure all the bases are covered we might as well just clarify that there should be no:

and definately no:

Finally, perhaps all assignment cover sheets should sport a clear symbol to deter those would otherwise certainly attempt to plagiarise:

 

 Can't say fairer than all that now, can you?  Although I suppose, since we are meant to be in the business of student engagement, we should allow the students to utilise this same mechanism.  Perhaps we could issue them all with a card that they could hold up during a lecture at appropriate points?