You cannot say that with statistical certainty. There’s about 8 billion people who haven’t eventually died yet and all it will take is one of them to break that 100%. You should include a disclaimer with an error range or you might get sued by someone who spikes someone’s drink with dihydrogen monoxide and then they don’t eventually die for botching their assassination.
That said, the statistics are pretty strong. 99.9% is basically 100% plus wiggle room so no one can sue me, so readers should be aware that this dangerous chemical can also go by the name of hydrogen hydroxide and some food manufacturers try to sneak it by with the name aqua in their ingredients list.
I don’t think I’ve ever seen a pizza place sell small pizzas for a decent value. They price them to not sell. I’m guessing because they aren’t as predictable for the amount of volume you might need.
It wouldn’t have been cheaper to go for bigger (ignoring deals), but it wouldn’t have been much more and you’d have leftover pizza for lunch the next day.