I've only ever had one GA where I saw the other aircraft. I'm told, possibly incorrectly, that if PAX can see the other plane in the sky, its not the GA you want. (it cast a beaut shadow over us as we flew on different paths rather sharply. most becoming and pretty. I would include claims I saw about 35 rows of 'the scream' by munch here, but that would be like a fishermans lie. I just saw metal very close)
On the whole, if I was the Airline and one of these got reported to me, I probably *would* be wanting to put their number into some Database and do a cost settlement on brown-trouser cleaning later on, but then you see.. it probably happens 50/50 the other way too. So in the end, I suspect that these things don't go into a least-cost settlement bin, because frequent offendors should be de-listed, and anything else is zero sum so why invent a mechanism?