Cars are cutting you off on the highway. Your pulse quickens. You need to concentrate. What you really need is absolute silence—no phone calls, no music. In this kind of situation, a new stress-sensing system developed by Ford would shut down the distractions the moment driving becomes tense.
Fart danger is everywhere recent science fiction. First there was Greg Bear's novel Vitals, in which an evil Soviet conspiracy leads to targeted biological mind-control attacks. How do you know somebody has been taken over by mind-controlling bacteria? They start farting. Doctor Who took this idea a step further.