Most of the readerboard signs can be hacked. They are designed to be programed by driving up next to them and sending a new message via a wi-fi connection. Of course, that means they can be hacked. Just like voting machines.
I’ve read about how some are hacked by just opening that rear box and finding the password written on the inside of the lid. Because you can’t expect workers to remember all of the passwords to these important devices.
The first one I ever read about being hacked was the following, which was in a story about how people would physically hack into them to change the message:
Unfortunately, younger people don’t get the joke of this particular hack (as was pointed out in the story) 😀
Who are you? | What do you want? | Why are you here? | Where are you going? | Do you have anything worth living for? | Who do you serve and who do you trust?