[HamiltonJay]

I don’t know, I’d want to say this was intentional, since why would someone fill ballons with a flamable gas when inert Helium will do the same effect.

However I just don’t know.

[mvpel]

The US has the world’s largest helium reserve, outside of Amarillo, but it’s being depleted rapidly:

http://www.sciencedaily.com/releases/2008/01/080102093943.htm
http://www.cbsnews.com/2100-205_162-6797764.html

I’m sure it’s quite expensive outside the US, and the prices have gone up significantly over the last several years.