Ever heard someone say "don't leave the window open, or insurance won't cover us if we get robbed"? 

Put simply, gross negligence is the insurance term for any damages that occurred due to (your) human carelessness.

And although the basic plan still reimburses you a percentage of your coverage, this add-on makes sure that you are fully covered if an insurance incident was somehow caused or enabled by you (you left on the stove, lit candles etc...). 

No shame in getting it, since we're only human after all (wink).