reasons off the top of my head:

* its not hard to run ```phpdoc -d src/ -t docs``` if someone wants to, and it really has nothing to do with what needs to be in the repo. I dont think thats any harder for them, in fact i think its easier and more flexible. 
* makes the repo more complicated. 
* there are many things they might want to run that we wont have in there either.
* to run stuff for our build in travis we can just add a phpcs command to the before_script list in the yaml file. and if we have something more complex it could be in a simple php script that gets called in before_script but I cant imagine it would be. simple is golden

i am strong opinioned on this.