Does reduced trimming trump centering?

[Snowman]

Originally Posted by steve B

I am confident. Every manufacturing process leaves evidence of itself.

it isan exact science.

A guillotine cutter and a home or even pro paper cutter will leave a different cut. A sharp blade leaves a different cut than a dull one. Die Cutting which is used for most modern cards is different than any of them. Same for rotary shears.
The only exception I'd make to detectable or not would be using a professional guillotine cutter on cards produced using that type of cutter. And that has some very real challenges if you're trying to trim an individual card.

Size doesn't really matter, within limits. What matters is edge quality and placement. The edges ae also directional.
You were very close with the rough edges on a trimmed card being in the wrong place. I would bet that those edges are not in the correct direction

Yes, of course there are differences in cuts from each of the various blades you mentioned and how dull or sharp they are. If you cut a card with the wrong type of blade, it will obviously stand out. What you seen to be overlooking though is that you cannot distinguish between two cards that were cut by two different guillotine blades or two cards that were cut by two different ream cutters, etc. There simply isn't that much variation in edge textures of cards to begin with. It's very easy to duplicate most cuts. Hell, you can even buy the same cutting machines that were used by Topps. There's a reason these guys are getting trimmed cards through by the thousands. It's because they're not detectable unless they're amateurs who completely botch the cards up.