Average Joes are not going to have to track all there btc spending. IRS has no way of tying you to a anonymous bitcoin address. Nor do they want to waste time on it. Pull your head out of your ass.
Shhhh.
I prefer it if others offer themselves as sacrifices, it sates the beasts hunger and so lessens the chance of it hunting me.
I am thinking it might be best to report at least some if not all. I mean, if you are using Coinbase I'd say it's probably a good idea to report, but maybe you have more than one wallet...