Rules say yes:
Gases including flammable, non-flammable, toxic and compressed
gases, new, used and empty gas cylinders, butane, ethane, refills for lighters, fire extinguishers and scuba tanks, life jackets, nitrogen dioxide and carbon dioxide canisters (culinary foaming devices & soda stream),
1. All flammable compressed gases are prohibited e.g. blowlamps; butane; lighters and refills containing flammable liquid or gas; ethane; gas cylinders for camping stoves; hydrogen; methane and propane.
2. All toxic compressed gases are prohibited e.g. chlorine; fluorine etc.
3. All non-flammable compressed gases are prohibited e.g. air bags; scuba tanks, carbon dioxide; fire extinguishers; neon and nitrogen.
It’s compressed nitrogen that rear shocks were getting picked up on.