People make themselves collateral damage. No matter what you might have to hide, if you have any sense at all you're going to give it up if you're faced with something far worse. She's not under the bus by accident or by being in the wrong place at the wrong time. She's under the bus because she couldn't come up with a plausible timeline, and her story didn't stand up. It also doesn't help that she was the last person known to see him.
Maybe she thought they'd mark him present after seeing him there, and nobody would be able to place just when he went missing. That way she wouldn't have to come up with such a wide timeline.
The easiest way to make sure you never fall under the bus is to lead an upstanding life.
I'm not disputing the above in the case of TMH; it certainly appears bad for her.
But as a generalisation, I think you are mistaken. Ask yourself what Kevin Fox did to throw himself under the bus? He led an upstanding life, he told the cops the complete truth and he spent 8 months in jail for it.
Well, he was the father of a three year old, Riley Fox, who was abducted from the family home while he was asleep. When he realised she was missing, he hunted through the house, yard and neighbourhood before calling police, which seems to me to be a perfectly natural reaction.
Then he took Mark Klaas's widely known advice: he completely cooperated with police. Big, big mistake that led to 8 months in jail while the real perp walked free and unsuspected (and did commit further harm against other children).
After 14 hours of intense and coercive interrogation, Kevin Fox made a false confession. No, he should not have done that but people can only endure so much physical or mental torture before they snap. Kevin Fox was obviously pushed into snapping.
The police had a set of (probably unconscious) filters that led them to discard real, actual evidence, like the torn screen, the fingerprints (if they had bothered to run the fingerprints right away, it would have solved the case in the first hours of the investigation), the tennis shoes abandoned near Riley Fox's body that had the name of the perpetrator on them. A name belonging to a convicted sex offender.
The police also ignored that Kevin Fox's false confession was filled with contradictions, both internal contradictions and contradictions of the evidence.
None of the above raised any red flags with the investigators until Kevin Fox managed to persuade a Project Innocence lawyer that he was factually innocent. She took a look at the DNA test, which had been called inconclusive and figured out that the correct DNA test had not been done.
Once the correct test was performed, it pointed straight at the perpetrator. Whose fingerprints were on the Fox's screen door and whose tennis shoes with name on them were next to Riley Fox's body.
I don't believe that the police in the Fox case were innately evil people who were out to get Kevin Fox personally. I think they were well meaning officers who became so focused on a particular theory that they lost all perspective. Then they were able to justify to themselves that the use of any technique against Kevin Fox was justified because they saw him as an evil man who sexually assaulted and killed his own daughter.
And to me, that's the tragedy of investigative tunnel vision. Kevin Fox is obviously a victim. So is his ex-wife (the marriage between high school sweethearts did not survive the experience). So is his young son, who was subjected to coercive interrogation aimed solely at incriminating Kevin Fox.
But the officers involved were also victims. They were fired, they will no doubt ever work in LE again. And I imagine they felt a great deal of personal humiliation. Yes, they did wrong but I believe they did so with the best of intentions. They were under the influence of investigative tunnel vision and they didn't know it.
The thing is, LE with investigative tunnel vision never realise it.