No, and its your responsibility to protect both your dog from other people and other people from your dog.
That doesnt mean saying something, it means putting yourself in between them and getting physical if you have to.
If someone reaches for your dog, push their hand away and give a sharp 'No'. Its not assault and there is nothing they can do about it.
If they want any further discussion you state' animals can be unpredictable, leave them alone for your own safety.'