There's been recent debate about proposals to make it law that all dogs must be microchipped. One argument being levelled against it seems to be that people who breed and own dangerous dogs will ignore the law and that only law-abiding owners will comply. This seems to me to be the most bizarre argument. If you apply the same principle across the board no law will ever be passed because people who break the law will break the law and people who obey the law will obey the law. The suggestion that because some people will break a law then the law shouldn't exist seems ridiculous.
There may well be other arguments both for and against the idea. As someone who has never owned a dog I don't have a strong opinion one way or the other on whether dogs should be chipped. I do think this particular argument is a non-starter though.