I looked at the FT Glossary and Your Mileage May Vary wasn't in there. Technically many "ice" packs contain a liquid/gel of some sort. Whether TSA cares about it or not i don't know since I've never tried so instead of just saying it isn't possible to carry on an ice pack without putting it in the kippie bag I just put that the OP's experience may vary depending on who is working that day.