That is something that i find hard to trust on tribes you know, i have talked one to one with beard the creator of pizza token, he seens like a nice guy but i have yet to find any info that guarantees that they wont be able to change or alter the price when they want to.
Is kinda a hard pill to swallow because as someone born in venezuela, i have my fair share of "let's print more money" moments on my mind, and it never works out, it allways ends in messing with the economy :S