Some sandwiches are so terrible, or so stale that they should have crime scene tape wrapped around them. Which of course would be a good way to keep people from messing with a good sandwich too. Crime Scene Sandwich Bags will keep the hands of others off your tasty lunch.
It’s a psychological thing. Would-be sandwich thieves see it and they obey as if it really was evidence at a crime scene. This is important because sandwich theft is on the rise.