A non-policy electronic device policy?

The evidence that (a) we simply cannot multitask, and (b) in-class electronic devices probably hurt students as learners more than they help them, continues to mount. This is an issue we've addressed before. What options are there besides an outright ban on devices? One position: "it's you're funeral". Some require students to post their electronic notes. Others try to turn the technology to their advantage, allowing students to send questions electronically.

I'd like to share what I tried this term (and which seemed to work, based on my unsystematic observation):