During tournament compition, not all competors would agree it may have gone in IF flag was pulled.
For instance, you putt a ball up hill with a firm putt, no flag it hits back of cup and goes in. With flag in, it hits stick and bounces off. The ball did not go in, no woulda coulda, it did not go.
Pulling flag is alway the best option. You do hve a choice of leaving it in if you want when you putt. That the reason pulling flag has all ways been there. There Use to be a penalty for hitting the flag stick if putting on green too I believe.