From: US Midwest
I have not checked lately, but it used to be that if you watch your opponents number of naval units closely, you can tell when land units are boarding transports(or amphibious assault ships), and when naval units disappear through transport portals. You can use this knowledge to anticipate invasions, tell when the British are sending units to Egypt(and so when to Sealion), or if the US is reinforcing Egypt or going for Torch.
I don't have a problem seeing losses, as an opponent would have first-hand knowledge about that. But I think total number of units should be obscured with fog of war on, you can glean just too much from that information. I personally don't use it, as I believe it confers an unfair advantage, but it could be used and I am sure some do, if it has not been fixed by now. Can anyone confirm?
Lock up your wife and children now,
it's time to wield the blade...