One more thing
My nit-picking above aside, there's also the question about whether this is even the right (or even a good) solution to the problem. It's the same old Sir Humphrey logic: we must be seen to be doing something. This is something, therefore we must do it. Will this make it harder for thieves to sell on phones? Well it might make a marginal difference, but the black market being what it is, a thief will still have plenty of options for selling what they steal. Will it do anything to deal with the actual causes of violent assault? Of course not. For that you need a completely different, and much more expensive set of measures like more cops, better street lighting, and maybe technological measures like (silent) panic alarms in phones, automatic shutdown/bricking (combined with a reasonable mechanism to get a replacement phone) and so on. Unfortunately, fingerprint scanning isn't one of those technological solutions, IMO...