Re: 90,000 feet
Typical power pilot attitude. Airspace and traffic awareness is typically much higher with glider pilots than it is with powered planes. I cant even count the number of times I've seen a powered plane fly through a gaggle of gliders circling in a thermal on my fingers. Most often without ANY indication they even noticed any other traffic.
As for the complaints about color, most gliders nowadays have high-vis anti colission markings. A luxury I have yet to see on the many equally white composite powered planes that litter the skies on a good day. And keep in mind, if its VFR airspace, ALL planes have a responsibility to maintain lookoit and traffic separation. And whether you like it or not, if I'm circling in a thermal I actually have a right to keep circling and YOU are obligated to avoid me. If I'm right next to an airfield I might listen in on the radio, but I am under no obligation to report my position and many airports actually prefer gliders to NOT do so as long as they stay out of the airspace.
Same when landing, a motor plane has the luxury of a go-around. I get ONE try, and it'll end on the ground one way or another. And even though on many field the motor and glider circuits are separated and I will do my very best to avoid getting in the way I have had to avoid asshat motor flyers buzzing the circuit more than once.
As for transponders and contacting ATC, in many places small GA and glider contacts actually get filteres from the returns to declutter the screen. There is a good chance ATC cant even see me when I DO carry a transponder. Which makes keeping a visual lookout all the more important.
On top of that there are many vintage gliders still kept airworthy. Do you really expect someone to install a 2000 euro transponder into a plane that probably never ventures far from home and is worth probably about the same?