The "problem" had little/nothing to do with International flights.

UA was a MAJOR co-planner of that NEW airport (at least there should be sufficient 24hrs storage possibility for oversized luggage as skis - Colorado wants to increase the ski-touristic-business).

The final "solution" to my problem, as described, gave UA more logistic problems and did cost them more man-power-minutes than normal overnight storage.

In Europe competition achieved that all major airlines (UA included) offer "check-in the night before your flight" as a convenience/service.

And in add, when our flight first departed from the gate, it had to return again "because some cargo moved ..." as the pilot said - I am pretty sure they stored that cargo overnight - and I still believe that cargo (and storage of cargo) is the bigger security issue than passenger-accompanying luggage!