I suppose it triggers off your brain to see if you learnt that trick in a Muggle physics or chemistry class. Same way "it" triggers off your brain to see if you have at least a vague idea of what a spell does before making the magical bats appear.

I'm reminded of the Mage: The Ascension tabletop RPG. In that setting, Paradox forces inflicted very painful backlash on mages who performed magic that a watching "muggle" would find hard or impossible to believe in - so a lot of the game revolved around finding a way for your spells to look like plausible accidents. Cast fireballs near something that could have exploded on its own, give heart attacks preferrably to elderly or overweight targets, and so on.

The Hogwarts anti-tech jinx could be the inverted, less vicious version of it. If Harry gets around to seriously tackle it, perhaps he'll find the solution to be as simple as passing his tricks off as magical artifacts or Charms.