And do you think these facts are unclear to either the Catalan government organizing the referendum or the Spanish government sending in 13000 "police" officers to stop them ?
Yet the Catalan government moves forward (because that's how they got elected in the first place perhaps ?) and Spain is using violence to stop them (also illegal, but no way the courts are going to do anything about it, those officers do not have the right to operate there).
The Catalan government is not stupid: they know most of the voting will be stopped. They declared that whatever votes they can gather, if 51% vote for independence, they will declare independence, illegal or not, however many votes they can gather and once declared they will presumably move their own police force directly against the Spanish force (that Catalan police force far outnumbers the Spanish police).
That the voting is obstructed seems to virtually guarantee that 51% condition will be satisfied, whereas it would be a tossup at best if there was a fair election. It seems the Catalan government was gambling that Spain wouldn't take the risk, and they were right. Tomorrow Spain is the enemy, and Catalunya will be united under the separatist government.
Sounds like it's a pretty good bet that more violence is coming.
Europe has a huge problem. Europe's economy has been stagnant for the past 10+ years in the vast majority of Europe. There are only a few exceptions to that. Germany, the Netherlands, ... and Catalunya. Spain does not satisfy either the debt conditions or GDP conditions of joining the EU, and Catalunya does. But that's a trivial legal problem: when European politicians had to make the choice between more control and more people and their treaties (supposedly the constitution of Europe. heh), they chose for more control every single time. So Spain will be forgiven, and everybody will squint until Spain is allowed to stay. But Spain will obviously object to Catalunya staying in the EU. And if Catalunya separates, or even tries to and manages to make Spain look bad enough, many bridges might break. Belgium, the Flemish region versus Wallonia (in that one, Europe might lose it's capital). Scotland who might want to shortcut Brexit. Meanwhile, this will strengthen separatist movements in other countries (Italy, France, ... and those mostly want to leave Europe).
Therefore a LOT of things could break very badly if Catalunya separates and Europe is vehemently against, but they can't come out and state as much. The only government even a little bit willing to come out and show some support is the Belgian NVA, which is sort-of a separatist movement itself. The big question is what they'll do next.