[@Ashifili]

It's not really reality warping, like I said, a powerful suggestion. Something based on your perception of reality.

If he's not looking, how can he be 100% sure that he doesn't have one and that it isn't open? So, he would feel compelled to check, only then to remember that no, his pants have no fly.

Simply put it's like someone telling you that your string is untied while you are walking absentmindedly, you thank the person but when you go look you are wearing dress shoes, which means that they pranked you.

Or, in other words, Haruka's power is the ability to play the ultimate prank. Got it?