I have some questions about Sideboarding, especially in Limited sideboarding, that I would like to know the answers to. The speed at which players sideboard, and how much time is spent adding and removing cards to the deck can reveal a rough indication of how many cards are sideboarded. In constructed, typically this gives little information; it's easy even to misdirect someone who attempts to gain information this way (just spend as much time as it would take to sideboard say 12 cards when you're only switching 2). It's hard not to notice boarding is happening or when it is done, and one player inevitably is faster than the other.
The interesting question is what happens with Limited, and fringe or linear strategies. Two examples are Lost in the Woods (Innistrad dark ascension) and Mill. Say one player is playing heavy into mill. They're mulling over what to sideboard and notice the opponent having shuffled their deck and putting down a very thick stack of cards. Their opponent turned their 40-card draft deck into a 65-card one. Is it wrong to act upon this information? How would you even prove someone did, as it's not that weird to sideboard out a mill strategy when hate against it is universal due to the rules for Limited. Or, if you're the player playing mill, and the information is supposed to be hidden, whether you intended to cheat or not gets muddy when the decision to continue with mill or switch up the deck is strategically contentious.
Another example, which I don't know if it ever came up, is two copies of Lost in the Woods in the same draft facing each other, with either player not having any enchantment removal. If both players decide to stick with it or return to it in game #3, #4 or #7, whoever has the biggest library wins. And since you can add any number of forests, and see 49 cards using mulligans, and both players attempt to do this, thus the sideboarding never ends, or I guess whoever has the biggest hands (as in, physically) wins, which is just weird.