Why the sign then?

I entered a shop yesterday.
There was clearly a sign which says,


NO SMOKING.


Ok.
That's a normal thing in shops right?
Almost every shop we pass by or enter puts up a no smoking sign.
As I was browsing, I noticed a little triangle container.
And I thought 'hey, that looks like an ash tray!'
But it was impossible.
An ash tray in a shop that doesn't allow smoking?
Then, I went to take a closer look.
I not only saw an ash tray, but I saw one filled with cigarette buds.
The reason for this post?
Why put up signs we don't mean.