A lot of people are saying "we have zero evidence, so we must assume that both outcomes are equally likely" which I think is equivalent. It's saying that her words don't carry any weight as evidence unless there are also words from the other parties that confirm.
That's just common sense, though, to wait until you have heard both sides of a story? I don't think it is the same as implying somebody is lying at all.
Experience shows that probably both parties will think their version is the truth. It's just that they will both have selective memories.
No. If someone runs at me bleeding, saying they were shot, I call 911. I don't particularly need to hear the other side of the story. I would hope the courts listen to both sides, but in day to day life I think it's fine to make judgement calls about when you trust people.
I suspect you trust people all the time, but you don't feel comfortable trusting a person in this specific kind of situation.