Why do BioShock's Vita Chambers recognize the protagonists when nothing else does?
Rapture is the sort of place mad scientists dream about, a city that thrives on fascinating and ethically dubious technologies. One example is the genetic key, which allows Rapture’s security systems to recognize the DNA of founder Andrew Ryan and his relatives. It’s what keeps the protagonist Jack from being obliterated by guard bots (he and Ryan are third cousins or something, don’t worry about it), until things go horribly wrong and someone else takes over, turning the city’s technology against him.
That is, except vita chambers: devices that revive Jack whenever he’s brutally killed. They're also coded to Ryan’s DNA, so you would expect they were controlled by the genetic key too. However, even after the key switch, the chambers still revive Jack, and for a neurotic like Ryan that seems like a lax setup. This makes even less sense in the sequel, where a teenage girl adjusts a chamber to recognize blatantly not-Ryan DNA and revive a guy who died years before it was configured to him. We are talking about the same paranoid, despotic Andrew Ryan here, right?