Morosco,
I've read that such technology is illegal for use in theatres in New York, but I believe that there has been talk of a legal battle. They've put it in in theatres in other countries and apparently it works beautifully.
In the old days (and perhaps still now), doctors and people who might have emergencies of some kind, simply would leave their beeper or whatever with the house manager before the show. If a call or message came in during the show, the house manager would discreetly go to that person's seat and inform him. It's easy, quiet and provides a minimum of distraction to other audience members.
Why not put in the blocking technology and make an announcement a few moments before the curtain informing the audience that because of the blocking technology, they won't be able to receive any calls or pages during the show, but if any person needs to be reachable for some important reason, that they may check their cellphones and pagers with the house manager (who will be somewhere outside the range of the blocking) and he/she will be happy to field incoming calls and contact them if need be?
It might be a pain for the house staff some nights, but honestly, how many people on any given night would go to the trouble of checking their phones? Three? Four?
"What a story........ everything but the bloodhounds snappin' at her rear end." -- Birdie
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"The Devil Be Hittin' Me" -- Whitney