This is a simple sig that I've read many times that leads to some interesting thoughts.
This leads me to three possibilities.
One: The zoo of engineers. Enclosures with Civil Engineers, Computer Engineers, Hydraulic Engineers, etc. Typical visitors would marvel at how human they managed to appear. “Daddy, isn't it cruel to keep them in a cage?” “They are only engineers after all.”
Two: Engineers have very specific dietary requirements and random feedings may upset the balance. Salt, sugar, fat and caffeine intake has to be carefully controlled, and giving an engineer a chocolate bar at a random time may completely upset the balance. This could explain much about the stability of computers and other electrical equipment.
Three: Much like Gremlins, Engineers are known to metamorph into something even more scary if fed. Just don't do it.
A final possibility is that the sign is incomplete. “Please Don't Feed the Engineers to the Management.” It will do neither the management nor the engineers any good at all. Management will fail to gain any technical competence and engineers will be even less able to complete their paperwork.
This exercise in weird thoughts was brought to you today by the letter E and the number 9. Or perhaps it is yet another exercise in Drivel brought to you by Lynn Alford. You may choose.