In my professional ~20 year experience, throwing evidence in higher powers face that they changed their mind.. is not going to score you any points & give you a win.
Well guys you decided this at the meeting 6 months ago, that's why you aren't getting the feature you just imagined in your dream last week. Guess what, it generally doesn't matter. Stakeholders want what they want, business, customers and requirements evolve. Having "receipts" or thinking that throwing them in peoples face is somehow going to win you arguments is naive.
Having receipts is the difference between "oh I guess I didn't request that 6 months ago. but I want it now, so how much will the change order cost?" and "you're lying and trying to rip me off, you'll be hearing from my lawyers next".
Well guys you decided this at the meeting 6 months ago, that's why you aren't getting the feature you just imagined in your dream last week. Guess what, it generally doesn't matter. Stakeholders want what they want, business, customers and requirements evolve. Having "receipts" or thinking that throwing them in peoples face is somehow going to win you arguments is naive.