Skype at West Point with internationals and lack of security clearances and they are worried about secureness?
by happenstance ended up chatting with one of the goldcoat staff in a hotel pool, he was telling me that Skype was currently banned as it was considered a peer-to-peer program with a perceived fileshare risk.
Realistically, it's not, and it's widely used in more sensitive installations, and he indicated they are revisiting use guidelines.
As mentioned, there are other options in wide use if you just have to have video conference.
But for many cadets, for voice your desk phone is easiest. You have unlimited LD, etc. So there's not a reason to use skype to avoid Long Distance, etc. Each cadet has their own number/phone, and it will accept inbound calls.
Likewise, depending on your barracks & floor, you may or may not have cell coverage. And you don't have pockets in "As for class" or W/G, nor can you use a cellphone in most places during the week. So for Plebes, the cell is often less useful. (But that will vary with company, your room, etc)