Technically no. If you won't be on magic express your luggage can not be.
Now they do send the tags ahead of time that you attach to your luggage and you see it at your resort 2 to 3 hours after arrival because Disney gets it from baggage claim etc. I have to imagine they would pull it but might get very worried if your baggage arrives but your family is not checked in to ME in a timely fashion. They scan your ME booklet when you board so they will know if you actually got on the bus or not.
There is a "sticky" about this subject near the top of the Transportation Board. That is the only place this subject can be discussed, as it tends to get pretty heated. No harm done, but you can expect this thread to be locked up tight pretty soon.