Not Douchebag = Double parking in the deep end of the lot.
If it's OK because nobody needs those spaces anyway, then why not just park in the deep end properly, surrounded by all those empty spaces?
Whether or not there's plenty of space, double-parking means, "I would rather prevent a stranger from parking at all, than trust them to park next to me". That's douchebaggery, don't do it. Also, "plenty of space" when you park your own car doesn't mean there will be plenty of space throughout the whole day.
It would be like somebody's handing out chocolate bars and you take two of them. Even if there will be some left over, what makes you so important that you're the one who gets two? How much of a douchebag do you have to be, to think that the one perfectly adequate chocolate bar offered to you isn't enough?
I get it, you're worried some careless peasant will scratch your car and it will cost you a year of their meagre salary to get the paintwork redone. Well, the responsibility of that high-maintenance paintwork was your choice to take on when you decided to buy a clownmobile; it's not society's responsibility to provide you with twice as many parking spaces as everyone else.
I mean, I'll never have to park a car, because I'll never have a car or know how to drive, so it doesn't even affect me. But seeing that some douchebag has double-parked their car just makes me think, "wow, what a douchebag".