I voted. I can't talk about all the schools, but the ones I checked made sure (electronically) that you didn't vote twice, but of course there's a chance that some people did indeed vote more than once if for some reason they manually wrote down the name.

I suspect that will be one argument used by the Spanish authorities as to why the referendum was invalid.

What would you propose in a situation where voting gets you beaten, and schools hosting ballots get smashed up?

Sounds pretty amazing, with all the violence and militarized police abusing the voters, for some people to be dedicated enough to go through it four times