Search & Seizure Law 101: Just say No!!!
If a law enforcement officer pulls you over and asks to search your vehicle, You have the RIGHT to politely tell the officer “NO”!!!! By telling the officer “no”, the officer must have probable cause or some recognized exception under the law to probable cause before an officer can legally conduct a search of a vehicle. For example, a police officer can not just pull you over for a routine traffic stop, and then conduct a full search of your vehicle without some probable cause or reasonable suspicion to first of all stop you, and secondly probable cause to perform a search. However, often individuals waive this right by consenting to a search. That’s why officers generally ask you, “may I search your vehicle”. By stating yes, you have effectively waived any privacy interests under the 4th Amendment of the U.S. Constitution and under the Texas Constitution. By saying yes, you basically allow an officer to search your vehicle without needing probable cause to do such. Thus, if an officer’s search turns up evidence of criminal activity, that evidence can be used against you in a criminal prosecution. So in other words, don’t voluntarily make law enforcement’s job any easier to prosecute you. If law enforcement conducts a search without your consent and lacks probable to do so, then any evidence obtained as a result of the search generally cannot be used against you in a criminal prosecution. JUST SAY NO!!!

I love this! Let’s start our own nationwide “Just say NO” campaign. That’s a just twist of words against an unjust system.
The A.C.L.U. has a really informative free video on this subject and it can be found on youtube, thanks for all the information here.