Discrimination ? Hardly. Stray cats tend to fair far better than dogs for some reason. Dogs are far more likely to be picked up by the authorities, so would benefit from microchip identification.

As for ruff justice, I like it.

Its about ?20-25 to get it done at the vets for dogs or cats, and worth every penny. As I have said before, they can have their temp taken from it too, which saves the struggle on the vets table trying to do it via "normal" methods.