I have posted more than once that talking to the police in a routine traffic stop or other encounter is a bad idea.  Not surprisingly, this is an often reprised subject on other blogs as well.  Today I ran across a great post on this topic by Robert Guest, who publishes the Dallas Criminal Defense Lawyer Blog.  His post — "your cop is not cool" — hits on something I experience with many young clients.  An excerpt from his post:

Cool Cop/De Minimis Arguments- A very misguided hope that their cop will be "cool" and let the suspect go. Related to the "I just had a joint in my car, I thought I would get a warning", de minimis justification.

Most people expecting a cool cop have a story to tell about another cop who was cool, and let them or a friend go. A word to the public- your cop is not cool.

Most officers, especially traffic enforcement (DPS etc) live for drug searches. If DWI is the capital murder of traffic stops, then finding drugs is like solving a bank robbery. Cops love finding drugs. Watching their excitement on film leads me to believe some get high on busting drug users.

Don't consent to a search or volunteer information about contraband. Consider, instead, asking for an attorney or refusing a consent search.

I know you are nervous. I know that you think the recreational use of drugs is not a reason to arrest someone. But cops don't think like that. The love arresting you, and they aren't cool.

Robert's point is that cops have a job to do, and that job doesn't include a polite slap on the wrist.  In Oxford this "cool cop" scenario comes up regularly because (1) college students make up a significant portion of the population and (2) a good number of local law enforcement officers are young men and women.  Apparently, for college students, talking to a cop that is a member of their generation gives them a false sense of security.