PIC 1 - The German infantry kneeling in the woods can see the enemy quite easily..
PIC 2 - But when I order them to 'Hide', they can't see much at all with their faces planted in the dirt, and lose their LOS to the Russian infantry which instantly disappear..
(The tanks remain in view, so I think we can assume units on 'Hide' do lift their heads now and again for a quick glimpse and can't miss seeing tanks,but a mere glimpse is not good enough to see infantry)
Tactical note - I usually only use 'Hide' to try to break the lock of incoming enemy fire, and at the same time I cancel any fire order my infantry have got, and slap a minimum-arc on them.
It's my way of telling them to face-plant, not fire back, and to hold their fire lest they draw more enemy fire..