When there is more man-made stuff in the airspace, there is more chance of a collision if any of that stuff moves. "I said, she said, we met, we don't, it won't......" I risk being killed if your whatever-you-call-it collides with my aircraft. No matter where, or what altitude, or what safety measures you or others have taken. Until you accept the same risk, you have no right to increase my danger. Plain and simple, do you accept that risk? If not, you agree with me - that increased collision risk is unacceptable.