"If AMZN dropped $100 on the open on Monday". Why would I worry about monday. The expiry was today. I know you can get assigned , if price is outside long legs before expiration
There is a chance you will be assigned even if your short legs are out of the money. If that happens and the stock moves 100 points on Monday, you would be out (or possibly make) $10,000 for each 1 lot you were assigned on. That's why you should care.