Pretty interesting concept but I don't think that this will do anything towards getting Bitcoin legalized. The customers that pay for goods and use Bitcoin while doing so don't really need to have a Government saying that Bitcoin is legal or not. Plus with the rates of most exchanges, it's pretty expensive to purchase Bitcoin.
Bitcoins could get used by many people without the need of the petition being signed, this looks like a subliminal Bitcoin census and I am against that.
One of the problem with regulators is that they sometimes do not know how many legit users and normal people are using it. This may help them to find that. We can try, thats what we can do.
Regards
Hopefully this works out, the Government aren't usually within the same side of the citizens opinion unless the higher-ups approve it. Since this involves money then it will remain a slippery subject when talked about in the courtroom.
If there is a bunch of people signing the petition and physically making a difference between fiat and Bitcoin without that much violence then Bitcoin does a chance of legality. Maybe there will be a person who has the connections for that to be possible.