How another airline does it
I'm guessing that people posting in this forum haven't seen Ryanair's ruthless efficiency with cabin bags. With the advent of internet check in, gate staff at Ryanair look at each bag and if it looks remotely oversized, the passenger has to put it into the gauge. At many gates every bag ismeasured and Ryanair enforce a strict one bag rule - ladies' handbags included. There are always a handful of people who have oversized bags who inevitably arc upabout having to pay extra for it to go into the hold, but the gate staff are implacable, and security is never far away. It works because Ryanair see hold luggage as a revenue stream, but I suspect also see hold luggage as a barrier to fast turnaround times.
For all of Ryanair's perceived flaws it's punctual, and I've never had a problem stowing my cabin bag.