One of the fringe benefits of open sources an existing code base is that you have an opportunity to setting error_reporting on E_ALL | E_STRICT or perhaps rather just to 2147483647. When you do that you find small problems with your code base you missed the first time you sloppily wrote it. In my case, I noticed that date() was throwing strict errors.
Due to his resulting request to test the error (after submitting a ticket to fix the server's php.ini settings), he went about trying to test and see what the real impact of working with the date function was by developing his own simple benchmarking script. It runs through five different tests some with a default timezone set and some not. His results found that doing it in the script versus on the server's config didn't make much of a difference so he corrected the issue with a quick ini_set (or a date_default_timezone_set).