Well said.
I think that this is a case of the O.P. being overly-enthusiastic about security; stretching possibilities into stretching credulity.
There is an upper limit where everything is suspect of being corrupted or modified.
If a user wishes to view the world through this lens, they have every right to do so. But they do not get to conclude that if they did not see a file; it therefor does not exist. I have never petted a Giraffe.
That doesn't make them not exist.
(And as a matter of safety, it probably would be wise to not pet a giraffe.
Not saying I wouldn't... Just saying it would be wise not to...)