Rapaire's being silly. Everybody knows Dilbert's tie is really a radio transmitter that's sending out jamming waves to keep the Slughead messages from getting through. Sometimes the Slugheads use different frequencies in an attempt to circumvent the jamming effort. That's why Dilbert has two ties. One is to block VHF signals and the other is to block UHF signals. It's a much more elegant solution than wearing a tinfoil hat while at work. And it doesn't set off the metal detector.