Your point is valid only assuming the government wasn't aware of the thing and would have acted differently in perfect good faith, but real world ain't fairies and unicorns: politicians are blood and flesh mortals who can be corrupt exactly as every normal citizen. We'll never know the answer to a what-if different situation, but if I had a time machine to check, I'd bet everything that, had Snowden informed the government in advance, he would probably be dead of "natural causes" by now.