Comment by xipho

> question of whether it actually saves anything is clearly relevant

Agreed. Just like re-usable plastic bags are now possibly worse than 1-time use unless they themselves are used many times.

> A receipt that can be rotated is somehow a difference maker

This is the concept behind metro bus services in many places I've experienced, the driver glances at the color of your ticket and knows it's nature and whether you can keep riding or not. Don't know if that's a difference maker for conferences.

Looking for "badgers", or a syncronized icon instead of time/date etc., possibly coming at you in many different forms (phone, paper forms, etc) seems like it might be quicker. It might also cut down on people losing their badges (they are more valuable to them) and requiring re-prints ... which happens a lot, this is grasping.