That's the sad thing, there's not really a good way to know without being the subject of a landmark court case. And as one of my friends has told me "I never want to be the topic of discussion in a law class" and I very much agree with him.
It probably comes down to what reporting if any, is required. here is scant information on the FCC website. Community repeaters were around decades before cellular and CMRS services. It was a mom and pop industry before NEXTEL and all.
In south Florida, the dealers have licensed all of the UHF spectrum for "rental" services, it is tough to find a clean repeater pair. Then there are NXDN licenses on a single 6.25 slice that pretty much wipes out putting a DMR channel centerd near that spot.
I had a client who used three different radio shops for his county wide locations. The dealers each loaded the customers radios with all sorts of simplex channels he was not licensed for. Then there was the mystery repeater, on a tall building, shared by two entities, each thinking the other held the license. The last time it was licensed, Motorola was still in the licensing game, Mid 1980s or so. One of the entities pulled out the Motorola letter. I knew the folks in the memo, they retired 2 decades before.
I called the coordinator and he told me that there was so much unlicensed operations the best way was to set up a scanner and find a clear channel! Can you imagine? I said, nope, lets coordinate it properly using FCC records and if someone shows up, that should not be there, we will simply call the FCC to deal with it. The wild west.