I didn't say all expert witnesses are good nor did I claim they are all used in good faith.

Merely that, unlike in the invented scenario above, statistical differences in the random garbage that gets written to a disk across different tool or OS versions has been successfully used to place a time window on when exactly someone destroyed evidence.

I heard one argue that "zooming" on an image by adding pixels with an algorithm is normal, and he's had such "evidence" used in court before. I was a little horrified as someone who has worked on digital forensic software at a former employer. Adding pixels to an image is not evidence, you're fabricating something out of thin air, especially if its drastically smaller, its even more likely to be BS.

You know that defence can bring in an expert witness too right?