One time when I was playing an early game of X-com, I shot down a medium scout and my Skyranger was already on the way to a terror site or somesuch. After a long flight across an ocean and back (it was my only squad at this point) I was twiddling my thumbs getting the craft refueled. And just as soon as it's ready to head back out, the marker showing the crash site of that little ufo vanishes. My thoughts immediately turned to "Where the eff did they go?" and a whole range of possibilities opened up. What would be cool in the 1.+ versions, would be messages detailing the crash sites before you get there since I'm sure a super secret international organization can get their hands on surveillance of any kind, including satellite imagery. It would also be cool to click on the crash site and get updates on the situation like how many people have reported disturbance, level of government/civic knowledge and response, and stuff like that. Then, in the case of a crash site being too small to deal with in the midst of intense ufo activity to the point that it gets forgotten about, you would recieve a pop-up message letting you know just what happened to that ufo, ranging from "It's vanished without explanation" to "The local government mopped it up." I would presume that in each case it would be a bad mark against the Xcom-equivalent organization. I think it would be a good bit of immersion that wouldn't be too difficult to code, though not completely necessary, so it could go in afterwards.