Bathroom Graffiti - Is it Copyrighted?

I only have half the world's perspective on the issue of bathroom graffiti.  Being a guy I, of course, have only a minimal understanding of what a girl's public bathroom looks like, basically stalls,  lots of stalls   Beyond knowing there is a toilet in every stall  I've not spent enough time in the opposite sex's stalls to comment on the graffiti, if any at all.

Men's bathrooms on the other hand I understand. We display and experience a wide variety of bathroom poets, social activist, public ridicule and slander.  Some is humorous, some mundane, some devoid of any association with intelligence.  Over the years there have been some scribbles on the walls that have remained lodged in my memory.  Why?, I don't know.  I suspect either I've seen them in a lot of different places and hence have re-read them many times over, or perhaps during periods in my life I was unfortunate enough to be a captive audience by virtue I was working somewhere and used the same bathroom.

I have thought to myself who originated some of these gems.  Is toilet text considered copyrighted.  Is it plagiarism to re-write something you read on one wall in another bathroom.  Should the original author get credit.  Should it be noted like a bibliography:

Men's room, handicap stall  
3445 West Oakland Ave, 2nd floor, Anytown, USA., 
Author: Les B. Moore, 
Seen August 12, 1978.

Most are not signed, so most would be Author: Anonymous, but if you knew you'd get credit for it maybe people would sign.

Additionally, who carries a pen around with them?  It's not like most people have jobs that demand they have a pen or marker handy all the time.  Look around in a restaurant or mall.  How many men have a pen visibly on their person?  Not many. And even if you consider the suit wearing crowd may have a pen tucked in their jacket pocket, are they really the culprits of all this bathroom literature?  Nay, don't see it.  And what about the scrawling over the urinals.  Maybe you can operate the main drain with one hand, but I'd have to say you are pretty talented if you can piss and write at the same time.  Barring the talents of a few men, (which the lack there of may account for all the piss on the floor, they aren't really as talented as they think and don't care about pee soaked shoes) someone would have to finish their business and then take additional time standing in front of the urinal to write something.  How do they know no one is about to come in.  I don't recall reading a lot of unfinished writings, so most people must get them done.

I'd be curious if what I've seen has been seen my others.  Also, I'd like to know what others have seen that I've not.  I don't know this but sure seems like someone would of put a book together documenting these toilet treasures.  But then again after presenting such an idea to a publisher maybe they never could get past the plagiarism .