We cannot control technology anymore - MP3 players hidden in ears, mobile phones hidden up sleeves, televisions hidden in pencil cases.
But I remember not so long ago the excitement of the video in the teaching profession, especially when we all needed a break after a long term. At that time, bereft of ideas, we turned with relief to the school's one VCR.
We would book it. We would get the tape. Then ask a child to operate it.
Big mistake. First, their families all had machines at home long before you knew about them. Second, they've seen everything anyway.
I remember a PE teacher going wild in the drama studio. Helpfully, she had offered to look after the whole of Year 9 while her colleagues completed their reports. "I've got just the thing to keep them quiet," she enthused.
As you might expect, Year 9s couldn't give a toss. They were more interested in pulling each other's hair out. I can see their point. Who would ever want to watch a television in silence? At home, they would be doing everything from eating to arguing.
I learnt painfully that there is no class anywhere that is going to behave merely because you've got a video of The Wilderness Family.
The technology that we find so awe-inspiring is old and familiar to these kids. They are forever one step ahead of us.
What are you going to show them? Harry Potter? They've all seen it with a bag of popcorn at the movies. And, whatever they have seen, the one thing they will remember is the ending. They will announce it, too. Loudly. No point in watching it in the first place.
Shall we try an esoteric low-budget film from a banana collective in Ecuador, with subtitles? Get real. Don't forget that their sensibilities have been twisted by special effects. Nothing else matters.
You might look away during parts of Macbeth. But this is the only time they pay attention. They want to see the entrails. At home they have a flat screen as big as a flag. All you can offer is a dusty old box with crackly sound.
So when it gets to the end of term, don't do it. The words "Look everyone, I've got a video" should never pass your lips.
Always believe that you are more exciting and interesting than anything on the telly and you won't go far wrong.