When the dealer has an ace as an up card he or she
will ask the players if they want insurance, prior to peeking at his hole
card. The dealer will say "Insurance?".
If the player wants insurance, he can bet up to half of his original bet by
placing the insurance bet chips below the player's normal bet.
If the dealer has a ten-value card as the down card and thus blackjack, the
dealer will pay of the insurance bets at two to one but the player loses his
original bet. So it is basically a push if the insurance was half of the
original bet and the dealer has a blackjack.
If the dealer does not have a blackjack then the player loses the insurance
bet and the dealer removes the insurance bets immediately.