Part of that is because they probably get a hundred calls every year about a mountain lion being spotted when most likely it was just some feral house cat running across the road and the person doesn't know what they're talking about. And even if it was a lion, what are they supposed to do? They can travel something like 30 or 40 miles in a day. "Thanks for the call" is about the only response there is.
I don’t think regular house cats get that big to be tall enough to look over woven wire with all four feet on the ground in a ditch.