If we consider a virus to be the transport mechanism only, we will likely see payloads that we would identify as time and logic bombs, buffer overflow exploits, and Trojan horses.

CNN: Technology - Analysis: Understanding viruses

Rep. Eric Swalwell, D-California, criticized the logic behind the move, arguing that threats posed by bombs do not mean knives aren't dangerous.

CNN: TSA chief faces critics, says new knife policy will stand