United Airlines has put some muscle into enforcing the rules on what size bags can go in the overheads. The airline says it's responding to complaints by passengers who are frozen out of space by others with oversized bags, or crushed in aisle congestions while they are stowed. More bag sizers outside security, and turning the oversized back to check at the counter, not at the gate, are part of it. More details from the LA TIMES.
United says it's not about bag fees, and it's getting mostly positive responses online. Personal note: United is my gold standard for boarding, simply because instead of calling groups and having everyone crush in on the gate, they've installed lane markers for Group 1, Group 2, etc. and that makes it easier for everyone.