Perfectly fine with DL and other airlines charging for checked bags. I carry-on 95% of the time and am not interested in having my fares go up for a service I do not use.

That said, I can see how this new "enhancement" will play out...

"Oh, we're sorry Mr. SOBE ER DOC, but your bag doesn't fit in the overhead so our valet staff have checked it to your final destination. You can pick it up in baggage claim when you arrive." On only buy approved size cary-ons but I can totally see this happening.