Artemis Fowl and the Eternity Code has the following lines -

"Cameras have better eyes than humans. Did you ever see a TV picture on television? The camera breaks down the pixels. If you go down that corridor behind cam-foil, you're going to look like two people behind a projector screen."

If the above statement by Foaly is correct, then why did Butler use Cam-foil while he was threatening Arno Blunt in the prison? It was also mentioned by Sid Commons that they might check the tapes.

Question - Why did Holly allow Butler to use Cam-foil if she knew that he would very well be visible when they checked the tapes?

Artemis Fowl and the Eternity Code has the following line of dialogue from Foaly:

"Cameras have better eyes than humans. Did you ever see a TV picture on television? The camera breaks down the pixels. If you go down that corridor behind cam-foil, you're going to look like two people behind a projector screen."

If the above statement is correct, then why did Butler use Cam-foil while he was threatening Arno Blunt in the prison? It was also mentioned by Sid Commons that they might check the tapes.

Why did Holly allow Butler to use Cam-foil if she knew that he would very well be visible when they checked the tapes?