For those unfamiliar with Dragon Ball Z. there were scouters that could sense power levels. Sometimes, the scouters would explode while sensing rapidly rising power levels.
Which... Okay, I know saying that something in the Dragon Ball universe doesn't make sense is sort of pointless, but why on earth would they explode? Are the scouters set to explode if numbers change too rapidly? Do they absorb some of the energy they're sensing? Is that how sensing energy works? Should the heroes be concerned about something bad happening to them just from sensing their opponents?
I know the actual answer is "because it's a cool visual indicator that says just how awesomely powerful someone is", but I can't help but try (and fail) to think of a logical explanation for it.