It's rare to have so many different frequencies overlapping. I've been flying around that area for over 30 years and frequency congestion really isn't a problem. Certainly nowhere near as busy as the Serpentine/ Murray Field area can get and that works. Better that than people in the same area on different frequencies.
As for the tug incident, the following weekend the same tug did the same thing to a student on a solo nav. Is it worth risking a collision by doing a non-standard approach than to take an extra two minutes and to use the radio?
When you call inbound to the other gliding airfields around there will be someone on frequency to give you a heads up about gliders in the air, runway in use, tugs about to launch etc and good communication. I don't know why they can't all do that.