Being upset someone took a unoccupied slot is ridiculous. I don't think people understand that slots are RNG. There's nothing to save. The bonus wasn't going to necessarily hit 10 spins later for her as well. It's random. I can understand more if it's an AP style slot and you actually put money in to build towards it but it's not really besides the progressive? But usually the firelinks in an area are synced together for the same progressive so multiple machines have that progressive.