That is not true about pushing or losing more than half the time. From my blackjack appendix 2 you can see that when the dealer has a 20 the possible outcomes are as follows, after the dealer peeks for blackjack, and based on six decks. Dealer gets 17-19 or busts: 59.4% Dealer gets 20: 36.8% Dealer gets 21: 3.8% So, the player will push or lose only 40.6% of the time. The value of a 20 against a dealer 10 is prob(win)-prob(loss) = 59.4% - 3.8% = 55.6%. That is more than the 50% you get by invoking the automatic half win, so you should decline the option. I address this option in my blackjack appendix 8, under the title casino surrender. For the same reason, you should also decline “even money” when you have a blackjack against a dealer ace. In both cases two birds in the bush ARE worth more than a bird in hand.