When I am in an important meeting I hand my phone to my assistant who takes a message. If it a life-or-death (in the business sense) problem, I can be interrupted to take the call.
I have blue-tooth so I can handle calls hands-free, but if the traffic is busy I let my passenger take the call.
99% of my calls are text messages so that if I am in a theater or restaurant I can simply read the message to determine if I should step outside to take the call.
I would prefer only text messages even if my house were on fire. I would hope that the caller dialed the fire department first since I rarely carry enough fire-fighting equipment to help in the matter.
Certainly if I were giving a speech my assistant would inform the caller, even my wife, I will call back in X minutes.
By the way, if I am at a counter and the clerk is on the phone, I tell him or her to drop the call and service the counter. It is not rude to tell employees to work.
I wrote an employee manual last year on phone use during working hours that may be instructive for some of your readers:
http://plancksconstant.org/blog1/2006/06/employment_manual.html
