Hey, those nazi Zombies are a serious threat. Road signs aren't so much, "hacked", as they are, "open hatched and typed on". There's a little keypad remote in there with a screen and everything.
Non Password protected:
Write message and hit post single message.
Likely password is "dots" > type it in and hit enter to unlock.
Non standard password protected:
Hold shift + ctrl and type in "dipy" and hit enter to clear custom saved passwords.
Not that I condone this sort of thing at all but when one needs to warn people about Nazi Zombies a brother's gotta do what a brothers gotta do.