Check Inflatable Life Jackets

[Kent]

And NO, the automatic one does not go off if it gets wet, it is water pressure that sets it off.  You must be submerged about 30" in water for it to go off.  I have been in frog chocker rain that has soaked me and the vest many times without problem. 

I don't think that this statement is accurate. "An automatic PFD will inflate when the water-soluble bobbin comes in contact with water releasing a spring-loaded pin that punctures the CO2."  You didn't inflate it in the rain because the PFD is designed so that water falling on top and sides of the vest will not reach the bobbin.  I have put an old bobbin in some water and that bobbin dissolves like an Alka Seltzer.