I was in Houston the other day and they were talking about "no-refusal" weekends on the radio. I had no idea what this was so I had to look it up. Apparently, the police are setting up the usual extra-Constitutional DWI checkpoints. If at these checkpoints you refuse the breathalyzer tests, they now are set up on site with a nurse, a notary, and a fax to a judge's office to obtain a warrant right in the field to take your blood.
I found this astounding but the local media seems to treat it as unexceptional, and it was almost impossible to find any real news stories about it that were not just rah rah support your local police. The best resource seems to be attorney web sites.