I’m sorry, I can’t answer your question, but I have experienced companies lying about their email marketing opt-ins.
I placed an order with a company (it was the NEC in Birmingham) and distinctly remember clicking the “I do not consent” box and got emails anyways. I contacted them and asked them to look into it, guessing it was a bug. They got back to me and said it wasn’t possible for that to happen, and I must have misremembered.
I signed up for a new account, explicitly ensuring I was opting out from emails, with a fresh email address then logged in to check my communication preferences - the account was opted in.
I contacted them with this information and they basically wrote me back apologising that I had been misinformed, but letting me know that they were still legally in the clear and that the checkbox was actually just a “nicety” that they didn’t need, and that they relied on legitimate interest rather than user consent for marketing.