No, I did not sign-up for any email notification by Princess.
However, a couple years ago, I did email Princess asking more information about them, because I always wanted to try something new. That probably did the trick.
I just can't imagine anyone being able to suddenly run away on a 16 day cruise without at least a few weeks advance notice. Maybe there are some retired and wealthy people who can just drop everything and suddenly decide to go on a 16 day cruise that is sailing in less than 4 days? But even they would have to deal with the booking process, packing their bags, arranging for transportation (to Ft. Lauderdale and back from Barcelona by air). Can they do all that in less than 4 days???