I was in Bagram airspace the other day, and we had a handful of TA's in a period of 5 minutes way before ATC pointed them out to us. TCAS is the best invention in the last 30 years. When you talk about the big ole goofy world, there is a lot of space, but the planes have to land sometime, usualy at an airport! They all get funneled to one point at one time in the same airspace. Hell yea, mid airs are something to be concerned with.