DUI example is strange. There are blood alcohol tests, can't really avoid conviction if you fail the test. What's the explanation supposed to be for all the acquittals?

The way you say it, it's like you think that more and more acquittals is evidence of guilt, but that doesn't make any sense to me.

Repeated arrests would be no accident of chance, but those repeated acquittals would even call into question a conviction in the future. Something is going on to generate false accusations.