I'm not sure if you're serious, but some friends and I launched weather balloons with a payload (aprs broadcasting location) twice. Tons of fun, and there is a bunch of software out there you can use to estimate the crash location.
On the first balloon we failed to acquire enough helium, and ended up "floating" the balloon in the upper atmosphere overnight. Our prediction system kept indicating it was going to land in Africa.
If you mix hydrogen and helium, say 50/50, the risk of any fire is minimal. I wouldn't smoke around it, but I wouldn't be afraid of it causing a fire in a crash. Looking at the recent shoot down, the brief white cloud suggests to me that they might have been using such a mix.
We seriously considered it, but were most worried about issues while we were transporting it to the launch site.
And amusingly we ran into the helium issue because our initial vendor didn't have any available, forcing us to buy a bunch of smaller, lower pressure containers from a party store. We miscalculated, assuming there wouldn't be anything left when the pressure equalized..
I realize that, but the Hindenburg disaster happened when it landed, and a balloon that's not carrying cargo or people doesn't need to land gently. It can jettison the hydrogen before it gets too close to the ground.
