It would be very easy to do.
The first thing that comes to mind is Vegas.
Vegas, yes. But also any buffet, anywhere. Golden Corral, Luby’s (southern chain), etc. They could also infiltrate the production end.....Tyson and Perdue chickens, Ore-Ida potatoes, McDonald’s burgers, packaged salads.....the list goes on. A metropolitan water supply, or even bottled water would be fairly easy to tamper with. Really frightening scenarios to consider.
Vegas? nah they wouldn’t touch Dirty Harry’s house.