The problem you're all missing with cell phone gps apps is that if you're using your phone, people can call you during your round. I keep my phone off during my rounds because I'm there to play golf. "well Bob, it's 125 to the bunker on the right, and.. hold on I have to take this, it's the wife.."
Yeah I understand where you're coming from here but thats never been a problem for me. My phone is on silent and if I do get a call I simply ignore it. I cant turn my phone off just in case my wife has an emergency or needs to contact me asap. I cant be unreachable for 4 hours especially with a 1 year old at home that loves to climb stairs.