No Hand Grenades Please

So as I am walking into the Casino of the border resort hotel I was staying at, I had to pass through both an X-ray machine and a metal detector. Alongside the metal detector was a sign with 6 items not allowed inside the Casino.

1) No Hats Allowed
2) No Photos Allowed
3) No Cellphones Allowed
4) No Knifes Allowed
5) No Handguns Allowed
6) No Hand Grenades Allowed

Damn!! I wanted to take my hand grenades in with me when I gambled but  I was forced to check them  with security!

 The sign was a variation on this one:

You got to wonder how safe a place is when they actually have to put up a sign that says no hand grenades allowed, is that actually a big problem? Do people really travel to casinos with their hand grenades?