Sure, but just because these things happen doesn't mean they can be solved by publishing more stuff.
Every pilot must be capable of buying a paper map, but many (most?) are not on the internet so they will never get notams, or traditional aviation weather (they get it off BBC TV).
Like I say, Class G is Class G. Everybody has to find a way of co-existing with their neighbours. In CAS, IFR, FL150, you could close your eyes for the next few hours - even if you keep them open the chances of getting visual with another (relevant) plane is about 1%. You have to keep your eyes open so you don't fly into something big dark and nasty
In Class G, there are many potential conflicts: piston GA, gliders, very occassionally even a heli straying where it shouldn't be
You have the map with the big Gs on it, and ATC even tell you (sometimes) of known glider activity. But you could meet a lone-ish glider anywhere.
The Class G mid-air defences comprise of means to reduce the risk. 1) Fly above about 2000ft (eliminates nearly all piston GA, microlights, etc). 2) fly above the clouds if you can (the most effective method by far - eliminates nearly 100% of piston GA and - in the absence of mountains - 100% of gliders). 3) Fly
in clouds (statistically - UK - 100% effective; eliminates some 99% of piston GA, and most if not all gliders). 4) Don't hang around the circuit (most mid-airs happen there).
If I was flying at say 1000ft, I would be dodging all kinds of traffic, constantly. I know a lot of people like to fly low, presumably for the view, but they must decide on their priorities in life. And with any surface wind, it can be damn rough down there.
If everybody had a transponder, or an ADS-B transmitter, there would be an excellent technological solution, but this is some way away, especially with gliders.