Go Smoke,
I understand where you are coming from on this, however I would agree that you are being a little too hard on turniphead even if he did set himself up for it.
Perhaps there is a little more to this though than just your side of the story. I find it hard to believe that someone would just go straight through a danger area, intentionally, without getting the required info. I also find it difficult to believe that people actually use the goto function on their gps without checking where it is taking them. Maybe I'm naive, but I do find it difficult to believe.
So that leaves us with two possibilities.
1) The pilot thought they were somewhere other than where they actually were, or
2) The pilot believed that they had done all that was necessary.
If 1) is correct, then this is a navigation issue, rather than a planning or inconsiderate issue.
So how might a pilot believe that they had done all that was necessary?
Well, I'm unfamiliar with D129, I don't have a chart to hand, and I don't know what the entry for D129 in the AIP is. So this is just pure speculation.
But I take it, your gliding site is not the reason for the danger area? This is purely a guess, based on the fact that Danger area status isn't given to any other glider sites that I know of. So presumably it's due to some other reason. Someone mentioned a military base/airfield.
Now we should not forget that a danger area is just that. Dangerous. It's not restricted nor is it prohibited. A pilot is perfectly entitled to fly through it, but obviously should have obtained the the information on any activity taking place in the danger area before entering it.
It may be possible that the pilot called up the appropriate service (someone mentioned Brize Norton) and was told that the dangerous activity was not taking place at that time; perhaps told that the military base was closed. If that was the case, I would say the pilot was perfectly entitled to fly through the danger area.
Then the question arises about the pilot flying through a glider site. This is completely separate to flying through a danger area. I understand from previous posts that the glider site is marked on the VFR chart. Is there a frequency published on the chart for the glider site? If not, perhaps it would be a good idea to suggest to the CAA that one be included. If there is none, does your club mention to the authority charged with giving info on D129, that the site is in use that day, or that a parachute drop is about to take place? If not, and perhaps you do, but if not, it would seem like a good idea.
I don't mean to criticise you. That is not my intention. I'm just saying that, on the assumption that D129 is not there to protect your site, and that you're not the nominated frequency to call up for info on D129, it's a little hard to know what precautions the pilot took before going through D129. To assume it gives you protection is a big assumption.
The issue of flying through a glider site is a separate issue.
dp