...and I'm sure there are many house rules... in either taking the 'share-half' concession on the even-money bets or the 'en prison' choice.

My "100 CORRECT" reflects Carlos' explaining the option -- though not mandatory (required) at any casino, I should think.

The whole purpopse of my post was to bring about what Carlos said as being a true fact... and that because not known by both you or David should not be confused by the reader that there is no such option even though that such rules 'might' exist, somewhere, as you noted... Now it's known the option exists as Carlos explained it...