Why So Strict?

During the end of May, every year, the seniors go a little nuts.  They don't have any more academic challenges, or they just stop caring about them.  Since college is just around the corner, they get a little stir crazy and have mentally already moved on.  Because of this, some feel the need to introduce a certain amount of disrupting chaos into their fellow student's days and cause their senior class to be remembered.  This comes usually in the form of senior pranks.  Each year, different groups of seniors decide to rebel against the school's rules and throw something down the largest stairwell, cause a disturbance in the cafeteria, or cause another form of mischief.  Every year, the administration of the school needs to have some kind of consequence ready for misdemeanors.  For one thing, police surround the school for the last two or three days of class for the seniors, just to make sure that nothing out of hand happens.  Last year they rode around the school on ATVs.

This year, there were only 3 senior pranks.  One guy dumped pornography down the largest stairwell in the school, another guy put on a gorilla suit, went down to the cafeteria, and danced on a table before being caught by the security people and teachers, and another duo printed dozens of copies of a list of the most attractive girls in the school.  All were clearly out of place and distracting; no one can deny that.  However, none of the pranks directly disturbed classroom learning, and were meant to be amusing.  

The pranks this year were not as large scale as some in the past.  For example, last year students dumped thousands of bouncy balls down the stairwell.  It was funny, but the janitors had to clean it all up.  The reason for the weaker pranks this year lies in the potential consequences.  I heard from multiple students that if they did a senior prank, they would be suspended for a week, not allowed to walk at graduation, and arrested.  Then, colleges could revoke their admission.  I heard from my adviser that the police couldn't arrest you unless you broke the law, so I'm not sure about that part.  

All of the students that I have talked to agreed that pornography is never an appropriate or even slightly amusing prank.  In addition, it is illegal to distribute adult material like that to minors.  The guys who made the list could have hurt a lot of girl's feelings, but I don't think that it is illegal to print such a document, even though posting it without the school's permission may be against the rules, sort of like graffiti.  But the guy in the gorilla suit still perturbs me.  I don't see how what he did warrants the same punishment as the guy who dumped BBs down the stairwell and hurt someone when they slipped on them.  What the gorilla guy did was not illegal, did not hurt anyone, did not damage school property, and did not require cleanup.  It only served to make others laugh and have some fun.

So why can't the administration determine punishments for senior pranks on a case-by-case basis?  It would allow fun, innocent, and harmless pranks to continue, while the illegal, dangerous, and destructive pranks would be eliminated.  How could the administration handle the situation better to allow a reasonable amount of freedom here?