When an opponent moves their mouse cursor over a card, you will be able to see a card sticking out with a teal halo.
Many players have a habit of mousing over their combat tricks as soon as their opponent clicks on their blockers. (This helps them play faster and therefore grind gold/rank faster.)
To bait out information, simply click on your blockers as if you were going to block. Your opponent may instinctively mouse over their combat trick (e.g. Rapid Shot) as you do so. To make it less obvious that you are trying to bait out information, un-assign and re-assign blockers as if you were “thinking” about various blocking permutations.
In Bandit Queen / Stonescar aggro matchups, this can be helpful in figuring out whether or not the opponent has a Rapid Shot in hand. If you have a torch (or other fast removal spell), you may wish to block later on a turn where you are able to torch the unit that the opponent casts Rapid Shot on (leading to a blow-out as the opponent loses 2 cards to your single card).
Hopefully this trick helps you grind out a slight incremental advantage when playing against Bandit Queen decks.