I am not sure about this one. If a cyclist don't wear a helmet, police can choose not to issue a ticket as they are endangering themselves but DUI drivers are endangering others as well...
So where should the line be drawn? Not doing roadside check then how to discourage DUI idiots, what is the dis-incentive? Besides whatever penalty placed on the DUI offender after the fact won't bring back the life or lost limb of victims....