A more questionable exception to the Fourth Amendment is the exception of "vessel searches," where, not only is the warrant requirement inapplicable to brief stops of vessels, but also none of the safeguards applicable to stops of automobiles on less than probable cause are necessary to allow the stops of vessels. (Findlaw, 2005) This exception can be seen during 'drunk driving' stops, where all vehicles are stopped and drivers are screened, tested, or simply asked questions to determine if they are intoxicated, for the purpose of community safety.

However, since such searches occur randomly, without probable cause, merely depending on which cars are randomly selected, this exception...

It gives police the incentive to stop more vehicles, without probable cause and even to conduct such vehicle stops in a potentially biased fashion, although they are supposed to be random, simply to catch more criminals. The more innocent people are inconvenienced, the higher likelihood one criminal will be found, but this goes against the intention of the law, which is to protect individuals from being searched without probable cause.
Works Cited

"Valid Searches and Seizures Without Warrants." (2005) Amendment Four. FindLaw. Retrieved 26 Oct 2005 at http://caselaw.lp.findlaw.com/data/constitution/amendment04/03.html