If I feel your meeting is relevant to me, I'm listening and you don't have to worry about banning laptops. If you don't think i'm capable of deciding whether a meeting is relevant to me, fire me because I'm bloody incompetent.

If your meeting is not relevant to me, I'll try to get out my laptop and get some actual work done while my time is being wasted or if we meander into areas that are not of relevance.

If you ban laptops, and for some bizarre reason I still have to attend and your meeting is not interesting to me, i'll code on bloody pen and paper and enter some of that code into the computer once I get back to my desk, or i'll try to do SOMETHING productive. Trust me, you don't magically have my cognitive attention...

I had a consultant/workmate try to ban laptops in her meetings. No prizes for guessing whether I think it was the laptops or the meetings (or the consultant) that were the far bigger waste of time/attention/money...

Hire competent people and let them decide what the best use of their time is...or at least admit that you think its justified treating other's in the workplace like children...