As stated above the anti-collision markings are mandated in France, and they have been proven to work! Fluorescent orange is not a color in nature and it stands out against a snowy or cloudy background. There are called High Visability marking for a reason. There is an article somewhere on-line about the effectiveness of these markings. France has mandated Flarm now and had a significant reduction in collisions.

Take a look at the Schleicher web site, they offer a LED strobe strip in the vertical fin (it is part of leading edge so no aerodynamic penalties). With an LX ACL controller the strobe fires when there is a Flarm alert! I am surprised all manufactures do not just include this unit is the base price and not even make it optional.

The big sky theory is as valid as cold fusion.