Agree with rickair. Those guys are almost impossible to see unless/until they lift up a wing. The other day when we had our close encounters, there was talk in our jet of filing paperwork against those guys. I had to remind my guys that this could only be harmful to our careers since we were technically the ones in the wrong. ICAO/FAR regs shouldn't be used in place of good situational awareness and judgement. Frustrating. I don't want to sound like I'm trying to discourage grassroots/general aviation here. Far from it. However, that doesn't mean that everyone who shares the sky shouldn't have a high level of SA.