What the parent comment (and some siblings) are saying is that the file open dialog's behavior can probably be modified by the application that calls it, e.g. f

What the parent comment (and some siblings) are saying is that the file open dialog's behavior can probably be modified by the application that calls it, e.g. faking the effect of the user clicking Open on every single file. That could maybe be prevented by keeping the relevant sections of memory marked as read-only, and maybe it already is.