My sister and I flew from Cusco to Lima a few days ago to avoid a 24-hour bus ride. At the beginning of the flight, as usual, a flight attendant instructed passengers to turn off all electronic devices, including cell phones. Since I was carrying our only phone, my sister encouraged me to follow the instruction. I told her I wouldn’t.

I’ve refused to turn off my phone while flying for a year or two now. It’s mostly stubbornness on my part, but it’s borne out of my belief that doing so doesn’t matter. So many phones remain on through any flight, including during takeoff and landing, that if they posed a real hazard, flight attendants would check every phone personally and the instruction to disable them would be more emphatic. As it is, I have to believe that phones don’t affect the flight, and passengers are asked to turn them off only so they won’t miss other instructions while they’re yapping during takeoff and landing.

But since I don’t want to cause a crash, I’ll happily turn my phone off for all flights when I learn that its signal could actually mess with signals the pilot needs. Unfortunately for flight attendants, I’ve read that that’s not the case. Apparently, cell phone use is only prohibited during flights because chatting in the air would piss everyone off. Four years ago, the FCC was prepared to allow in-flight cell phone use when public reaction scuttled the plan.

I don’t talk while the plane is taxiing on the runway unless I have to, and I won’t turn off my phone unless I should. If there’s a real reason phones should be off during flights, please let me know. Until then, I’ll hope that people can’t talk during the flight but that attendants stop asking me to do the unnecessary.

Similarly, here’s hoping the M.T.A. wires all New York City Subway stations for cell phone use and never does the same for its trains.