It is not that easy - and (from my limited experience) it is imperative that a DL representative is with the UM at the only critical spot: immigration. This is where the trouble sits and this is where they might just deny entry or even send someone back. All after that is a piece of cake.
Not even a "gate pass" would make it possible to meet the UM at the boarding door. As I said before, the only exception to that rule I have witnessed was a medical doctor who took over a patient directly at the airplanes door.
UM works fine,
I'm not asking about UM service, the problem is they WONT provide it, the moscow office, i did not call them myself, but they said something like applied to late (right after purchasing a ticket), can't process paperwork in time, too many UMs on the flight already, all of the above, SU is fond of stupid communist-style bureaucracy it seems.
Maybe they will be able to purchase UM service at check-in though, but they were told no when trying to pre-arrange that