United Is Serious About Carry On Sizes

United has a new warning message on the online check in about carry on bags. The airline must have finally noticed the large contraptions passengers have been attempting to shove in overhead bins recently.  I applaud this move, but the real test is with gate agents using the bag sizer and not letting large bags on, then charging for a checked bag.  The rules aren't new or hard to find, but just need to be enforced.    

Carry On Bag Reminder

UPDATE:  They also had messages on the self check in machine and on the boarding gate monitors.  None of the gate agents checked the sizes though.