That doesn't help if you want to carry a bunch of alcohol you buy over there.This won't happen because of the time consumed and the lack of infrastructure necessary to collect payment
There exist's a 'parallel' hack to avoid paying checked baggage fees. If you know or suspect your flight will be full, take it to the gate (when was the last time someone at the counter actually asked you to put your carry on in the size checker?) and when they ask for volunteers to have their carry on checked through to your destination, simply volunteer. You have to plan for it, though, because I never want anything valuable to be in a bag that is allowed out of my possession. If it actually won't fit in the overhead and they do not ask for volunteers just board late and feign a bewildered inability to find space for it