Apple iMessage ‘edit’ and ‘undo send’ buttons risk enabling sex abuse: attorney
nypost.com
nypost.com
The real risk to users seems to be the opposite: Message deletion, "view once" functionality etc. can create the (false) impression that text and media sent on these platforms are more ephemeral than they really are: The recipient can always take a screenshot.
That was fun. But generally, both parties have to accept the screenshot you have is authentic, otherwise you just have some text on a piece of paper which might convince a jury.
Apple might be able to provide the original ECDSA signature from their server-side logs, but even there, nothing changes with editable/deletable messages: If that capability exists, it will continue existing (unless Apple somehow starts dropping traffic logs specifically for edited/deleted messages).