Taking C02 Cartridges on Airplanes

A student of mine who was flying to Seattle from the East Coast inquired if he could bring his inflatable PFD with him with the Co2 cartridge. Not knowing the answer, I posted the question on Facebook and immediately received 30 comments.

The TSA lists on their site the following info: 
Small compressed gas cartridges (Up to 2 in life vests and 2 spares. The spares must accompany the life vests and presented as one unit) - OK for Carry-On & Checked Baggage.

Many who posted about their experiences said they had their cartridges taken by TSA officials.  One had the entire waist inflatable PFD taken as well.  Some had a few positive experiences.

Since like anything with these things, you can bring yours but it may or may not be taken.  Plan ahead for finding a new cartridge in your destination if yours is taken from you!  And probably best to separate it from the PFD to you don't lose both.