I am curious about something....

My guess is that the main functionality of the little blue light on the side of the ECONOMY seats is to tell the FA that someone has a device plugged in and it has to be unplugged for takeoff and landing. Is that correct?

If yes, the light does not seem to be very reliable. I have seen people having devices plugged in and the light stays off.

Sometimes I even see people at exit seat have devices plugged in during takeoff and landing. If the indicator is not right, it is hard for the FAs to enforce the rule. That seems hazardous to me if we need to evacuate.