Many years ago a colleague had a similar situation at YBEV, he was landing on 16 and a glider landed at the same time on 08. They just missed each other. He was on the correct frequency which at the time was Perth Centre (I said it was a long time ago) and the glider was on the "glider frequency". Could this be a contributing factor? I can't understand how two aircraft at an uncontrolled aerodrome (which I note has a CTAF but is not mandatory for carriage of radio) could possibly not be aware of the other unless they were on different frequencies, or not transmitting at all?
I have had a glider tug not on the CTAF at an aerodrome where it is compulsory to carry radio cut in front of me on short final without a word - no idea they were even in the area until he filled up my windscreen and not responding to any radio calls before or after the incident, which was a matter of feet away from a midair, so perhaps on the "glider frequency" again?