I wouldn't bother. The amount you can earn from these campaigns are quite small, even for Legendary ranks.
I don't think no one will harass you for such a unusual income that no one is sure about.
Bitcoin is largely unregulated in the world and it will be difficult to regulate it once they make a significant effort.
This amount is also pretty small, so I don't see why someone would really care, as the whole signature campaign economy is very small.
But then again, I am not a lawyer, I have no idea.
Sure, the amounts you can get from signature campaigns are very small, but some people have been making bitcoin gains since the early bitcoin signature campaigns. Back then you could make up to 1BTC a month just posting in here. A lot of people have asked this before, since they now find themselves with a lot of money made posting on some internet forum, so if you want to diversify and buy real estate... how are you going to buy your house in the beach if you don't report your gains?
I don't know anyone that has gone through this, so im pretty scared that they will not accept the explanations given (that the money was made on an internet forum) so im not going to sell anything for now unless they have clear guidelines, otherwise be aware that you are the government's guinea pig and you have to expect anything.
First of all, I would keep track of all the payments you got on signature campaigns, and save screenshots too of the threads, I guess that would be enough proof. But then you would need to prove that you own the addresses in which you got paid... does the government accept signed addresses? do they even understand the process?
This is all too new and I have no idea what to expect, so like I said, im holding and not diversifying until it's perfectly clear what's going to happen, otherwise you risk that they confiscate your money the very second it hits your bank account, and they may (or not) accept your explanations. If they decide they are not clear, you may lose your money... im not looking forward to lose money that I earned perfectly legal, that is why im simply holding and watching and learning about it. It is again, only sane to hold your coins to nto be a guinea pig, until your government clearly sets the guidelines for special cases like signature campaign gains.
Im interested in how this thread will develop. We need more information on this topic.