The problem here is that a person using this automated tool is not being given the required information in order to decide whether the code they are re-using is a "substantial portion" of the software it's taken from; in fact, they aren't even being told they're re-using existing code at all.

This does not relieve the person using the code of the responsibility to make that determination, so anyone who is re-using code shown to them by this automated tool is doing it without having fulfilled their responsibility under the license. The fact that they don't know they are doing this, because the tool is not telling them, doesn't change that.

> People who publish MIT software know they're basically giving their code out with basically no strings attached.

No, they aren't. The license has terms. Using an automated tool that doesn't tell you when you are re-using existing licensed code, or whether your re-use is within the terms of the license, doesn't mean you can just ignore the license. It means you're re-using code without knowing whether or not you're violating a license.

> Reusing a snippet doesn't require reproducing the MIT license.

In light of Google v. Oracle going as far as the Supreme Court I find your confidence in this quite astonishing.

SUBSTANTIAL PORTIONS can mean the core five lines of some key algorithm buried deep in a 1000 line wrapper library with a bunch of language wrappers.

I don't interpret "substantial" here as affecting the 'de minimis' requirement for infringement, as that would require other language.

I'm pretty sure every court will instead interpret the word "substantial" in the MIT license as referring to the concept of "substantial similarity", which must be demonstrated in any copyright infringement case - https://en.wikipedia.org/wiki/Substantial_similarity

I distribute software under the MIT. "Basically no strings" != "no strings". I expect attribution for any derived program which has substantial similarity to my software.

I regard the presence of the word 'substantial' to indicate that the license applies to even modified forms of the software. As that Wikipedia link points out:

> Under the doctrine of substantial similarity, a work can be found to infringe copyright even if the wording of text has been changed or visual or audible elements are altered

What counts as a "substantial portion"? Personally I'd say that a function is substantial, whereas one or two lines would not be.