> The problem is that innocent people could go to jail because they fall into that 81% of incorrect matches.

No. This is a fully-general counterargument. You could say this of everything: 'innocent people could go to jail because of X!' This is true and irrelevant, because it is true of both good things and bad things, and not even wrong. It is sheer concern-trolling. The question is whether X works well enough. Nothing in OP or your comment remotely establishes whether it does or does not. Citing '81%' is merely throwing out scientific-sounding rhetoric. (It has numbers and it looks big, therefore it must be bad. It would be the same if it was 98.1% or 81% or 8.1%.)

So again: is 19% not enough? What is enough?

Bueller?

Bueller?