Description:
------------
From manual page: http://php.net/manual/en/info.configuration.php#ini.max-input-vars

> If there are more input variables than specified by this directive, 
> an E_WARNING is issued, and further input variables are truncated from the 
> request.

A note should be added similar to this:

"""
Note that in order for the warning to be issued, the error_reporting directive must be set to include E_WARNING in php.ini/.htaccess either globally or per directory (it's not enough to set it via ini_set())
Also, in order for the warning to be displayed, **both** the display_errors and display_startup_errors directives must be set to true in php.ini/.htaccess either globally or per directory (it's not enough to set them via ini_set()).
"""

I suspect the second part could be even argued to be a bug, but either way, it must be documented here because it's far from obvious.