This is uncool at many levels.
Breathalyzers are known to be very inaccurate (take a sip of a drink, wait 5 mins, blow, get an off the charts reading).
Intoxication varies a lot by individual (hence most places use sobriety tests like balance, etc), using only one metric isn't useful. One guy is passing out at .03 (but is legal), but another will be at double that and score above-average on proficiency tests but the law calls him intoxicated? It all depends on where your start point is (granny's driving ability reduced by 75% is different than your ability reduced by 75%), and your body's specifics.
For those of us who actually believe in the 4th amendment, the idea that merely driving through a public access area is enough Probable Cause to be stopped, and refusing an illegal search at that point will result in the police forcibly taking your blood is horrific.
More reason to avoid Florida, America's Wang.