A lot of people like to say not to judge by past actions, but isn't the best predictor of future behavior past behavior?

I think this at least warrants discussion.

1) When has not knowing someone's past ever come to bite you later? 2) What would you have done differently? 3) What determines if past actions are a red flag or not? 4) Is it worse to possibly risk missing out on a good partner by judging them for their past, or to ignore the past and have something bad happen that could have been avoided?