Hmm, just looked at Philly Auto Show web page and see this:

"Please leave your firearms at home to avoid any issues when going through our metal detectors. Per Pennsylvania Convention Center policy, only on-duty, uniformed police officers may carry any firearms inside the building (regardless if you have a permit to carry)."

I go almost every year and this is a first. I've been to other events at Convention Center with detectors and screening and some there was nothing, no pat downs, no detectors, etc. Oh well afraid it was coming.