Totally Agree, it's a pretty sad state when we're looking for magic tech solutions that can be heavily mitigated by simple behavior changes like bringing water, bringing bags and coffee mugs.

When i visited Germany you bought a bag if you didn't have one and it seemed everyone had them. In the US grocery chains knock a nickel off your total for all the bags you don't use. I don't think saving 20-40 cents is a huge motivator for people. If all grocery chains charged $1 per bag used, behavior may change.

Ideally we should try to motivate people into proper behavior and make it part of the cultural expectation.

It's important to remember the order of operations are listed in order of importance. 1. Reduce 2. Reuse 3. Recycle

Sometimes i forget mine too, we're human but i reuse those when i can and stick them in my car, backpack etc.