A few observations from one who used to fly gliders in the UK - now flying both gliders and SEP in Australia.
The licensing requirements for radio use in the UK are very intimidating to someone who has not gone through a full power PPL training - I would have loved to talk to ATZs, etc, but was regularly told that without that license I risked prosecution, so I stayed quiet - I also avoided all ATZs, class D, etc. I would have prefered to have a restricted glider radio license though.
Any glider pilot showing poor airmanship and not complying with the rules of an ATZ should not just be spoken to - it probably won't do any good, but take it up with their club CFI.
My understanding is that in the UK, all flying is baned unless specifically permitted - this makes it a privalege, not a right. Pilots abusing their privalege to use any airspace are bad news for all, whatever they fly.
Flying in Oz, I'm terrified by the fact that most power pilots seem to believe that RADIO is the principal means of providing separation when VFR. I also know from experience that a lot could be done to improve the effectiveness of lookout for all, but especially power - I re-trained my power instructor in this at his request as I was always seeing many more other aircraft than him whilst getting used to all these new controls and instruments.
What really confirms this reliance on radio is seeing a pilot instructed to go-around by the tower use the radio before reaching for the power !
I was taught to Aviate, Navigate and Communicate in that order. If i'm too busy doing the 1st 2, you won't hear from me until safe to do so, not forgetting that I've probably screwed up to get to that point, so sorry in advance if it happens.
Most flying here is at common fields, with set circuits, radio calls, etc. It doesn't cause a problem, however, I will and must cut inside if the powered plane in front insists on a 747 style circuit. Usually, ALL fly the same circuit (left hand.
Finnaly, new gliders can be critical on weight, even if that can carry 200kg of water - the issue is not max all up, but max landing weight - big commercials have the same problem - they are usually too heavy on takeoff for a normal landing