lucy24 - 8:24 pm on Mar 22, 2013 (gmt 0)
There's a third possibility. This happens with or without query strings. Periodically you'll see the googlebot asking for something like
:: shuffling papers ::
The search engine is testing whether your site returns a 404 when the page genuinely doesn't exist. In the case of php pages, the fix almost always lies in the php itself. If the parameter itself has meaning, the script has to return a 404 when it points to a nonexistent page-- like a post whose number puts it somewhere in the summer of 2016.
If the parameter has no meaning-- or if you don't use it at all, but someone else does-- tell search engines to ignore it.