As I have two Fruit of the Murphy Loins, I find the cell phone to be indespensable to the modern parent. The ability to coordinate my movement with my other leader has saved the day on more than one occasion - most recently when I summoned breakfast at the chess supernationals. But I find that it does reinforce a lot of bad behavior in people - poor driving, incessant chattering, loudmouthery, just general obnoxiousness and cluelessness. Last night when we were leaving a restaurant, a gentleman was talking on his cell phone squarely blocking the exit door. We were not quiet entering the vestibule; my loud "excuse me" caused no change in his location; only when I reached around Sir Clueless to shove open the door did he move slowly out of the way without apology or even any acknowledgment of our existance. I have no idea what he was discussing, but I know it wasn't that important.
People, let's be aware out there.