Isn't it leaking detail about internal policy about whether incorrect sudoing is getting reported or not though?
This is a pretty short diff and it clearly does NOT do that, unless you're saying they went back later in another commit to add this. They removed the message in all situations. The string "This incident will be reported" has been removed from the source code; it could not possibly print that message now.
Is there more to the change than the linked commit? Because if not, looking at the code change I don't see how you could possibly be correct. There is no additional logic/branching that could be checking whether sudo sends mail or not, just a string change.
It was added back in a later commit but only prints if the mail is configured.