How bad does the damage from the false accusation need to be?

One I'm fond of pointing to as evidence that they happen is Tracy West accusing her ex Louis Gonzales. He spent three months in jail while it was being investigated, and only got out because he happened to have a very heavily corroborated alibi for the day that left only a 6 minute window during which he would have had to travel a total of 2 miles, obtain a duffel bag full of forensic countermeasures, subdue and rape the victim, dispose of said duffel bag in a manner it would never be recovered and return. And that 6 minute window was not when she originally said it happened, until they allowed her to revise her statement which became much fuzzier about when it happened. Also there was evidence that she was researching the way she was tied up in the days leading up to her being tied up exactly that way. By all appearances this case was about a custody dispute over their kid, and despite the case being dropped because it was physically impossible for him to have done it she still got to use it against him because fucking family courts. He eventually got a finding of factual innocence from CA courts and had the entire thing expunged from his record - to be clear, this essentially requires proving beyond a reasonable doubt that you could not have committed the crime. When he was interviewed by an LA paper about the case, he'd developed an obsession with being as publicly visible with as much paper trail as possible at all time, just in case because of how lucky he was with his alibi from this case (if he'd eaten before he left to get the kid, his alibi wouldn't exist and that alibi is the reason he only spent 3 months in jail).

How about Brian Banks? Kid with a real chance of going into professional football, Falsely accused, threatened with 41 years, plead to 5 years + 5 probation + registering as a sex offender on advice of his lawyer. The accuser sues the school and wins $1.5M. 9 years later, his accuser contacts him on Facebook and they speak. He secretly records the conversation, in which she admits to having lied but refuses to tell authorities that because she was afraid that they might make her pay back the money. The video gets released publicly and the Innocence Project gets involved. He goes on to briefly join the UFL and then NFL after not having meaningfully played for 11 years (time that would have been the prime of his career if not for the accusation).

Speaking of the Innocence Project, what's your opinion of them? It tends to vary for left leaning folks - either they like it because a lot of the people exonerated are POC or they hate it because a significant majority of people exonerated by it were imprisoned for some flavor of sexual assault. Go look at their list of cases: https://innocenceproject.org/all-cases/ According to the site when filtered for sex crimes 184 of the "more than 250" people were imprisoned wrongly for a sex crime. 124/184 of those exonerated by the Innocence Project that were imprisoned for a sex crime were misidentified by an eyewitness. For sex crimes, that eyewitness is very often the alleged victim.