Yes, but I think GP's point is that it's unnerving that someone can give something to you, and then modify it without your consent. Sort of like how it's not c

Yes, but I think GP's point is that it's unnerving that someone can give something to you, and then modify it without your consent. Sort of like how it's not cool that Amazon can sell you a Kindle book, and then silently update or even remove it without your consent. (Not the same thing, of course, but it's in the same family of weird.) One potential real-world issue is that a text message conversation could be used as evidence of domestic abuse or of general harassment or threats. If the perpetrator can edit the message history for both parties at will, that's a problem. In practice, of course, there are ways to solve this problem, like the device keeping around the history of edits (Signal does this, not sure if others do), and the app can also limit the reach of this sort of nefariousness by disabling the edit function after a certain amount of time.