Snark aside, most text based editors have some giveaway or another. Even the GUI ones show syntax highlighting quirks that show that something is wrong.
This is only really relevant in unicode-aware terminals, without syntax highlighting and when you don't get to scroll between characters. IOW, it's really quite hard to do.
https://imgur.com/a/unKuOoK
Snark aside, most text based editors have some giveaway or another. Even the GUI ones show syntax highlighting quirks that show that something is wrong.
This is only really relevant in unicode-aware terminals, without syntax highlighting and when you don't get to scroll between characters. IOW, it's really quite hard to do.