Ink Replaced

We bought an ink replacement this afternoon, but now we are worried about the safety of the ink.  We don't know how Brother managed to sabotage the last cartridge from his hiding place, so what if he is able to get to this one somehow?  Ink is expensive, and we can't waste any on Brother caused sabotage.  We would set a guard, but the human's offering to show a film in just a bit that all of us want to watch.  What to do, what to do?  Brother should be ashamed of himself for putting us in this position.