Reward cards seems pointless to me, all it did was to encourage spendings, in which they used all the information collected through your spending to map up your spending behaviors and tailor their marketing strategy to market more useless things to you.

It used to be a decade or two ago that a person with thick wallet might be a well to do guy with a wallet full of money. Now a person with thick wallets are most likely having nothing but cards that encourages you to buy more useless stuffs and keep you in debt.

Hence to answer TS question, I don't give a damn if the cashier takes all my rewards points, as far as I know I don't want my spending habits being collected and analyze by stupid corporations planning to sell me more useless junks.