I guess I will sometimes bet like this. Let's say I go to a casino and then double my money. I don't just walk away, what I will do is take my principle and then pocket that. I will then gamble the rest of the evening with whatever I have left above my cost basis, which sometimes I lose all of, but other times I end up doubling or tripling, just depending on the situation.
Smart strategy, it's has a little risk involved but it's smart, gambling is strictly based on luck, the reason why I don't just double up my funds and leave is because doubling your money and quitting for the day doesn't guarantee that you will be in profit especially if you are still going to gamble the next day, you might lose the profits you've earned the next day or that same week.. sometimes I just decide to go beyond tripling my funds that same day if I can because I know that it's all based on luck