It's been noted at least a half dozen times in this thread as to why cops ask you to extinguish cigarettes.
Stop playing stupid.
Have you ever heard of a cop being assaulted with or harmed in any way by a lit cigarette? Ever? Just be sensible and adult for a moment and think about that.
If a cop has cause to arrest someone who is smoking, then there is cause to have that person put out the cigarette. Otherwise, what does a cop who is standing outside a car in which the driver (or passenger) is smoking have to fear from the cigarette? In the worst possible scenario a cigarette could be used to effect minor level of pain, but so could a kick in the groin, a gouge with fingernails, a straight punch in the nose, a thumb in the eye, a bite, or a diversionary mouthful of spit right in the face. Encinio had
no cause to expect anything like that from Bland.
There is no acceptable reason for Encinio to tell Bland to put out her cigarette. Bland was intelligent enough to be well aware of why he did it and it understandably offended and angered her.