@dm7 saidWhy? You don't get it over the board. You're expected to notice. After all, you know your opponent's move, so you should be able to work it out in just a few seconds.
Can I suggest something a little more "Eye Catching" when my opponent has put me in check. Just putting the word in red and bold rather than grey maybe? Anything that catches the eye without causing too much irritation.
Or do you expect your opponents to shout "fore", sorry, "check", when you play at the club? I'd consider that a distraction, and warn him for it, if one of my players did so too loudly.