There are plenty of vacant frequencies
that's not quite true. Even though not published anywhere, most possible frequencies are being used somewhere for something... and if it's as a company frequency. Why do you think the new radios have to have a diffent channeling? More frequencies are needed then are available, but there should be standard frequency for particular things like air-to-air in all countries!
for example, the following are the "official" special frequencies published in the German AIP:
121.500 emergency
ONLY
122.800 air-to-air
122.300 Training flights at an airfield
123.425 training flights for hanggliders, Ultralights, etc.
120.975 other flights for hanggliders, UL's, etc
122.250 balloon flights
126.725 parachuting
in glider flight we have the following:
123.500 training at an airfield
122.500 cross country glider flying
123.150 training outside of an airfield area
123.350 non-training glider flights
123.400 ground crews
Some of these above frequencies have been designated to glider airfields. I know of 5 fields within 50 km of each other that have to share the 123.150.... especially during aerobatic tows and heavy traffic days you hear almost all fields and you can't tell which is which or you get blocked out! One field has managed to finally get the 124.000. Because of fields sharing frequencies, there is normally a restriction about using it no farther then 15 NM and 3000 ft GND.
I have no idea who "officially" has the 123.45 but I know that many people use it....
Westy