I often joke that I don't like the word "spying" – it has such negative associations for what can be just taking an active interest in someone. Just like gossip is a rather unhelpful word for "discussing someone who's not there".

The TV star and sometime chef, Gordon Ramsay, has admitted planting (or getting his son to plant) a camera in his teenage daughter's bedroom to make sure she's revising and not making out with her boyfriend [see footnote]. "They seem to be spending a lot of time revising and yet the results aren't … So I said to him [son: Jack]: "Look mate, here's 20 quid, go and target your big sister's room and put that camera right at the top left-hand side of the wardrobe.'"

Of course, Ramsay is either joking or stupid. You don't plant a camera and then admit to it. The first rule of spying is: you never talk about it. Second, you only plant surveillance equipment to confirm what you already know. Ramsay once admitted to never changing a nappy. If only he had! He would be so much more in tune with his children's body language now and be better able to know if they were lying, without the aid of a GoPro high-definition camera.

In his excellent book, The Gift of Fear, Gavin de Becker talks about parents who plant cameras to watch their children's nannies. He argues that they know something is amiss, but they lack the confidence of their own judgment. They want evidence to back up what they already know.

What this all comes down to of course, is trust. But not in the way you might think. If you don't trust your child to tell you the truth, the reality is that they probably don't trust you to be able to handle the truth. Which is why teenagers often force an argument because they feel that they have nothing to lose in an already heated situation – they can say how they really feel in a row. The less savoury truth of that is that parents then have to look at their own behaviour. Why can't my children trust me? It's far easier, in those situations, to put away the mirror and get out a camera, or flick through a diary, or scroll through text messages. This makes it all their fault, their failings. Which is really convenient for the parent.

So, is it ever okay to spy on your actual children? Not really. Spying is a one-way process, it's all about gathering intelligence to use against someone. They won't say "gosh, thanks for that! I've learned so much about myself!."

If you spy on your children they won't stop doing what they're doing, they'll simply become more complicit at hiding stuff. After all that's what you're teaching them: duplicity.

• This footnote was added on 21 October 2013. Gordon Ramsay's representative has asked us to make clear that he made up a story about planting a camera as a joke to tease his daughter, who was in the audience.