Jerome,
I know that this has come up a number of times, but I just had a thought -
How about a text message (gamebox creator defined) appears if a piece on a hidden board is moved? The option to have that message appear at all could also be user defined. At least this way the other player would know that their opponent is tinkering with pieces on that board (and not just looking at it).
Hidden Pieces
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Hidden Pieces
"Fat, drunk, and stupid is no way to go through life, son."
-Dean Vernon Wormer
-Dean Vernon Wormer