On my recent trips to Europe I have travelled with a small suitcase which I check and a RS backpack (not wheeled) which I carry on. The backpack official dimensions meet the carry on standard. However, when you pack the backpack, it can get a bit "puffy". (Weight is not a problem) With airlines getting pickier, I am concerned about being forced to gate check.
I understand if the check-in counter agent makes me check it, I will have to pay for it as a second bag. What happens when the check-in agent doesn't say anything but the gate agent makes you check it? ( I have seen gate agents eyeing carry-ons but have not been challenged) Do you pay at the gate? Do they take the bag and get it onto the plane? Also, do they make sure if they do this, there's enough time for the bag to make it onto the plane? So far it's been ok but I will be flying United international for the first time and am wondering what the "gate-check" process is.
Thanks to anybody with knowledge about this.