I did this yesterday and entered a cell phone number not registered to any card and it was accepted. I could have used a burner phone so what does it prove other than I have access to a US cell phone and that I'm most likely not a robot?

Seeing that and the attestation form to me means their goal is to make the claim process more complicated and therefore reduce their payout. I didn't read the details but what if you don't have access to a scanner for the wet signature? Do you have to mail it to them on your dime? Also notice they worded the message "potential" fraud which may mean they haven't actually seen any.

So is this worth contacting Chase to complain about?