I don't think bag matching will have as large of an impact on carry on's as requiring them all to be checked. given the choice of standing in line waiting for somebody to search my bag item by item, or carrying it on, I think I may start packing to carry on stuff again, with a very small checked bag for the stuff that can't be carried on. Searching a small bag has to be faster then searching a large one by hand for checked bags. I can see it now, very tiny bags for razors, underwires, and nail clippers, the rest is carryon.