...In Russia.

That wouldn't work in the U.S. Changes to material terms in a contract generally informed consent (meaning, that the modifications are actually disclosed to the counterparty before they sign) or specific consent (such as a initializing the sections of the contract where the modifications occur). This is a basic part of the UCC, which all states have adopted in some form.

There are a lot of people on the internet claiming that you can get away with surreptitious material changes to a contract before it is signed. None of them are lawyers.

It's depressing to see how the system works. Sure, now there are different kind of terms in a contract, some are material terms and some are... immaterial? And conveniently, you can change some but not others in such a way that the banks and powerful corporations always come out on top.

I never heard of a corporation being forced to point out explicitly which lines in their long terms and conditions document have changed. But it's a well known obligation for regular citizens, because material terms.

> that the modifications are actually disclosed to the counterparty before they sign

Does Microsoft explicitly draw your attention to the fact that Copilot is for entertainment purposes? No, it buries that in a long document hoping you won't see it, and advertises it as the complete opposite, but it's ok when they do it, because those are not material terms, whatever that means. It means it's ok when the big guys do it, in the end.