Recently "we" had the autopilots disconnecting multiple times and all other flight director related "funny things" during flight in a 737 NG.
Announcement made; peeps in the cabin checked their phones; one had his "popular scandinavian brand" phone in Flight Mode.
Thing switched off; everything back to normal.
Currently under investigation.
Its better to be safe than sorry.
And anyway; if you leave on your mobile in flight you can disrupt the networks since you would connect to multiple cells.
Just put the bloody things on and give yourself some time off.
