I can't tell if you're being serious or not, but I actually do this. I've got a spork, a glass cup, a metal straw, and a fabric napkin that I bring with me everywhere. If I'm going somewhere I know that I'll want to bring food home I'll also bring one of my metal lunch containers.

I'm carrying a backpack anyway and this is a really small amount of things to bring around. It's a very small impact from a single person, but every few times someone will say "ooh, that's a good idea" or something like that and it makes me feel like the idea is spreading.