Pure Nitrogen could in theory cause problems with titanium........ 'cos of the lack of oxygen (titanium is in fact really, really reactive.... so reactive it forms a layer of protective titanium oxide before water etc... gets to it) . Don't think it would be a problem in a barrel though as it's hardly constantly saturated.
Nitrogen is dangerous to humans for the same reason....a leak of pure nitro will displace the oxygen, pure nitro..no oxygen (Co2 is pretty dangerous too...same reason) but a tank of nitro will displace a helluva lot more air than Co2, (more of it in there). Never thought about the bends though......... mebbe it's to do with nitrogen in high pressure hosing? you could probably get a syringe effect.
Hotpoint, have you got any info on the danger of the "bends" from compressed nitro? I thought you needed to be breathing it whilst under increased pressure for too much to dissolve in the blood. It's got me wondering, I'd like to read up.
We all need to respect our gas bottles a bit more......... even a leaky CO2 bottle in a confined space (tent, sleeping in your car) could mean you miss more than the tournament.