I do this all the time. I print two pages on one A4 sheet (or rather four, two on each side) and then fold them so they are like a leaflet.
That’s the main advantage of the system – you don’t have to design things differently depending on how big you want to print them. You can scale the same design to an A6 flyer or an A2 Poster.
I don’t think I do know actually. But here’s an attempt at answering this question anyway:
We are usually very quick at relating sickness or even discomfort to the food we ate at the time or slightly before. This is a very valuable trait to avoid food that is unhealthy or even poisonous. But it’s only based on correlation, so it can turn us off food that is not actually causing the sickness but we just happened to eat at the time.