To Top of Stack?

[Sgt Barker]

HMSC,

The original question is interesting. I have no idea of the correct technical answer.

For the other aspect I wouldn't consider it gamey to place a unit on top of stack on purpose to manipulate air recon, if indeed what you suspect is how spotting works.

[Dog Soldier]

From my experience there are some factors other than "who's on top" that determine what is revealed to air recon.

Considering the spotted hex....
1. terrain of spotted hex
2. whether there are vehicles or foot units in the hex
3. Morale and BF of the units in the hex. One poor morale or very beat up unit will cause the stack to be spotted.
4. Units in transport mode are spotted easier than ones that are deployed.

Dog Soldier

[Peter Szabo]

Regarding the original question - Yes, in my experience the color of a "question mark unit" is the color of the enemy unit on the top of the stack.

Look at it from the PoW of the programmer: there needs to be a simple rule to tell the color of the question mark, so why not simply look at who is on top.