Is this PBEM or live?
Why would you have control in a live game?
If you are refering to my post:
Live game.
Having 'possession' of an enemy concealment counter could happen if you prepare a VASL file, pull the counters for both sides including his OoB given Concealment counters. If your opponent uses a Concealment counter from the stack that you have pulled to put on top of one of his stacks, I *think* that you will be able to see what's inside because VASL remembers that you have pulled it, thus consideres it yours, and consequently let's you look beneath it.
But I may be wrong. I seem to recall that at some time (which lies years back) there was some sort of issue in that direction. As I have avoided pulling Concealment counters for my opponent but instead use a labelled blank counter to designate the number of Concealment counters for his OoB, I have not have any issues. At the same time I do not remember the details of that back issue any more.
von Marwitz