That's right, Scotland's referendum was not illegal. In fact, they had to get permission from parliament to hold it in the first place.
It doesn't much matter whether the Calalonian situation is legal or otherwise. Stopping them from having free will is the real issue. As we have seen numerous times, pissing people off and stopping them from doing what they want will not end well.
Dead right. Its hard to imagine the reaction of the Scots if police from the other UK nations suddenly arrived to stop them expressing their political opinions.