Multiple games selection is the high way to lose the bet because by selecting multiple games your risk level increases in proportion to the amount of games you select and by that you have a high chance to lose at most, although is not as if you can't lose with just one game selection but your losing tendency is low when you select only one game most especially when the odds are already in your favour.
But in multiple games selection, you may have guessed right with the first selection but the is a high possibility that your second and third selections may be wrong and that will ruin your total game plans, so for sure many games equal to higher chances of losing unless you are smart to make use of the cash out feature if you can accumulate some profits while the games are still on.
That is why online sports bookies are giving a high multiplier for each game that we add to the parlay. It's getting more risky as we keep on piling up a bunch of games. But you are correct, the cash-out feature could save us sometimes and I've done that twice in my lifetime of making parlays. Or should I say I was at the right time to cash it out? Because if I was away from my computer, I may never have had a chance to do that.
I am not the greedy type who will try to end a parlay while watching it happen. If I see good profits at x20 - x30, I am done. I won't risk it more and I don't have the courage to do so. But picking games in a parlay should also be deeply thought through. If we are trying to take advantage of the cash-out feature then we should also consider placing bets with a time difference of 30 minutes before the other game starts. Because, if it's a consecutive game where the other game in your parlay is still happening while the next one is also starting, the cash-out button will never be open.
That's what I observed from making a lot of parlay in my sports betting hobby.