Yes Van, I agree that not removing the queen excluder is not one of the best management practices for overwintering. That is not the excluders fault and it should not receive the blame, the fault rests with the beekeeper.
In answer to Mr. Wright's question, if no excluder is used the beekeeper must remove and harvest only the comb with no brood in it. If you attempt to produce comb honey an excluder must be used.
Do a search on YouTube for the UoG Beekeeping, they have a selection of videos that you may find helpful. Also, I would suggest you search for used books on beekeeping, in particular the ABCs & XYZ of Beekeeping published before 1980. This book will give good information on colony manipulations and practical management. For information on parasites it is outdated.