We joke, of course. The Spanish government has made this position abundantly plain several times over a number of years, and it still doesn’t stop idiot Yoons (and media pundits who should know better) from spouting it.
But this time, in the flesh, it’s really quite hard to spin a way out of.
The “procedure”, incidentally, would go something like this:
SCOTLAND: Can we join/stay, please?
EU: Do you meet all the criteria?
SCOTLAND: Yes, we’ve been a member for 40 years already in the UK.
EU: Welcome! There seems to be a seat free.