I'd tend to agree that most TX/RX communication issues are probably due to malfunctioning equipment, improper setup, etc. In general, I'd agree that cell phones should not interfere with our communications. But this does not mean they will not interfere.

RCKen, you cannot rule out any electrical device in close proximity just because it's useful or intended frequency is not close to our RC bands. Pretty much all electrical devices splatter out RF all over the spectrum, which is unintentional. This varies by device, maker and even model. Both of my parents worked for FCC field offices and did enforcement work. You'd be surprised at the wide range of seeming opposite devices that can interfere with each other, regardless of their intended operating bands.

I once produced a repeatable glitch by simply holding my TX near the RX. It only happened with one make/model of RX, but was interesting none the less. As soon as I backed off to about 5 feet, the Tx/RX worked perfectly. Both the TX and RX were operating properly otherwise as per the service center. I pushed the service center for an answer, and I got it. Long winded and technical, but in short, while everything was still within operating "specs", it was possible under the right conditions for my specific TX to interfere with my specifc RX at very close range.

Cheers!