TAG YOUR BAGS.
IF you land on time, let DME get the bags. Just pack what you need to go to bed and get up the next morning in a carryon. When you arrive at the resort, tell them you want your bags held till the next day.
Go to bed, get up the next morning and head for the parks. Your bags will be in your room when you come back.
Even if your bags miss the cutoff, they will be held at the airport overnight and picked up by DME the next day. Your bags will be in your room when you come back.
If they are not, then throw the clothes you wore the previous day in the wash, make a claim on your bags. If they don't show up the next day, then rent a car and make a Wal-Mart run.
If you land very late, then yes, go to the carousel and pick up your bags.
FOLKS, wasting time on vacation on "what ifs" is nuts!! In 99.99% of the cases you have wasted that time needlessly. Disney provides a service that saves you time and hassle. Let them provide it!! Only .01% of the time will you have to waste the time in the worse case scenario!!