They would reject the other proposals. It will pretty much sour your vibration around dating and everything else. Obviously, real-life dating is a lot messier.
Online dating doesn't work". Online dating done right is a focus machine. Then out of the blue, a couple of weeks later meets a great match in the grocery store they've both been going to twice a week for a decade. Online dating is nothing more than a massive and complex focus machine. Now, back to dating.