I don't think Spain would go after you if you show your faces. Unless this becomes as big as Bitcoin, which chances are nil. But what are they going to charge you witch, creating a coin? It's Spain, not North Korea. (I assume it's Spain.)
There are people accused of rebellion without any kind of violence. Multitudinary concentrations of peacefully people are considered as the beginning of the crime.
Doesn't sound like a free society. When I think of Spain I think of a country like the US, or England. But it's nice to know. I'm sure it is in every other way.