Hazmat regulations might be a problem as it is not an "issue" item by the "Carrier".
One example....had my PFD in my carry on as I was going fire fighting at the other end of the State. When I went through Security...despite the TSA guy knowing me, the Airline Station Manager knowing me....and even the Captain knowing me too....(or was it because they knew me....) the CO2 bottles in the PFD were not allowed on the aircraft.
After that....they went into the Hold Baggage.....out of sight out of mind...but a violation none the less.