Jargon is bad

Aaron was talking the other day on how using jargon is bad. The real problem is how to know if a word is jargon or not.

Example follows:

Yesterday my grandmother was bit by something she qualifies as jargon. She bought a new printer, one that can hold xD cards inside and print directly from there, when plugging the xD card she was told by the printer LCD "Do you want to format the card? Formatting the card in printer format will make it faster bla bla" and, she answered "Yes", and all the photos went to the heaven of photos.

The problem here is that we all know formatting means erasing, killing, vanishing the contents, but my grandmother did not. So should "format" considered jargon? Or maybe we should keep using format but on the confirmation question mention "erasing" too?