It depends on how the bot is “pinged”, and whether or not the bot’s base URL makes use of custom error pages, but in general, the answer is yes.
Writing a script in PHP to process a list of URL’s to check for 404 errors isn’t difficult, unless you also want to check to see if the page in question actually contains a bot. Then, it gets a little tricky, and a limited sort of AI would need to be used to determine how the bot is accessed to get a response, since there are no “set in stone” methods used by botmasters to allow interaction between a user and a bot, even among bots that are hosted from the same provider (e.g. Pandorabots). A bot page can be anything from a simple form with a text box and a submit button that uses POST/GET form submission, or could use a Flash interface, or even an AJAX interface; and other methods exist as well. It would make for an interesting challenge to write a script of that nature, I think.