The Tesla ran into me while I was crossing the crosswalk and then took off. I was able to capture their license plate. We tracked them down and were able to ask them, but they denied that they had done this. I sued them in civil court to cover my medical expenses. I happen to know what Teslas keep a video log of these. The defendant wouldn’t provide it willingly until we went into discovery and they were compelled to provide it, which made my case.

This is but one of infinite examples of the other party having evidence helpful to the other side and harmful to themselves.

> I happen to know what Teslas keep a video log of these.

You provide the court with that information, and the judge presiding over the case can (and almost surely will, if you're correct,) ask for the logs. If they don't provide them upon request, they're hit with a adverse inference, just as they would be if they withheld documents in discovery.

It's plain common sense.

Now, it's true that "you don't know what you don't know" and that discovery can be an investigative process, but for the vast majority of cases it's totally unnecessary. And, in very many cases, discovery will actually impede access to justice. In court systems without discovery, judges tend to take on a slightly more investigative role, besides.

The 95 year old lifetime appointment judge with dementia and cataracts: “Cars have cameras you say? In my day we only had daguerreotypes. We wore an onion on our belts, the style at the time. Request denied.”

This is an old tired stereotype. Judges are perfectly able to handle complex novel concepts such as technology. The judge before the oracle c. google case learned to program to gain insight, for example.

>The judge before the oracle c. google case

Exactly. The US justice system works for people with money.

> What do you know of this evidence and how do you know about it?

It's called "discovery" for a reason. You ask for everything you think might be relevant.