The system is fine as it is.
It's not the games fault if the players don't read the text in game or didn't play Fallout 2 (where it was forbidden to go armed in the city aswell).
Yes, text in capitalized red letters is barely readable, and yes, players all the time just look at their textboxes.
Loner timer and textbox info looks fine for me. At the beginning you were talking about legalizing weapons in those locations. These are two different things.
It's not the player's fault the game doesn't warn them properly
"You're entering xxx zone. Choose: @ Put your weapon from active slot to inventory. @ F*ck off, stupid dialogue box" and some timer, telling how soon guards will shoot you