Disabled Submit Buttons Ignored by Browsers or Rails?

If you have ever played around with disabling a submit button in Ruby on Rails using :disable_with on a submit_tag, you may have wondered if that tag is being serialized correctly so that you could actually identify it as having been the button that was submitted and disabled. The end goal of serializing would be to allow the server to correctly determine which button was pressed if you have more than one. Normally you can simply look in the parameter hash for params[:start] to see of the start buttaon was pressed. But then when you disable the button, browsers do not appear to serialize the response. One solution that Kevin Olbrich suggested using a hidden_field tag would be to add a hidden_field tag and have the Javascript change it’s value before submitting it. Is there a known workaround such as the one provided to this situation or have I missed something obvious?