[greendot]

Go fly in a private plane and leave your cell phone on. I do not fly IFR so I haven't had to rely in my ILS but it does destroy radio communications. Have you ever heard your GSM based phone pulse and cause noise on a close by speaker? Imagine that being pumped into your radios and into your headphones. It is painful to hear. If I was landing when it went off, it could cause me to react badly at a time when I couldn't afford it. Also, I could miss a call that there is traffic around.