Multi-tasking on the can

Some public bathroom stalls here have ashtrays in them.

Is this because:
1) People who were smoking going into the bathroom need somewhere to butt out so that they can concentrate on the task at hand
OR
2) People need somewhere to put their ashes when multi-tasking on the can
OR
3) Some other reason?!?

I've ruled out the option that people go into stalls to sneak a smoke, because you can smoke basically anywhere here.

Makes you wonder.