With respect to some early comments on this post about military traffic. I can assure you that on a daily basis we are witness to and have reported many situations of unknown traffic conflictions, whether they have their transponders on or not, which on some occassions they do not!! This has been confirmed by visual sightings and when the transponders are on, TCAS information. With the extensive military ops still occurring in Afghanistan and probing activity to the south towards Somalia etc., there is a lot of conflictions and potential conflictions. Add to this the fact that 70% of this traffic (majority US military) is 1) not talking to any appropriate controlling agency, 2) are flying across very busy domestic and oceanic air routes and 3) at non-conformal levels, the receipe for disaster is there. For example, the route from the operational area (for entry into to Pakistan/Afganistan) to Diego Garcia crosses all the Indian Oceanic Airways to the west at almost right angles and with no liason with either Middle Eastern or Indian agencies!
So the moral to the story is don't just look at the squizzy kit which relies on transponders being switched on
Heads up, eyes out, day or night, save that fright!
:o