ask the skier at Callaghan last year who had his in his pocket and had it turned off accidentally
y from banging while tumbling through the avalanche..actually you cannot ask him as he died and 50 folks and dogs spent 5 hours probing looking for the body.. you should turn off your phone when skiing  really and radios,apparently do not have as strong an effect as a phone.   you did forget to say the chest rigging should be arranged to have it as high as possible towards your upper core area where it will be better protected than on a leg...when tumbling you will protect your head and core naturally and use your legs to defend your core from trauma...regarding that Pieps you are wearing in your chest harness..there is a longer retraction cord in the harness sleeve if you tug a little harder...oh and if I was buried I rather they dig for close to my chest and mouth than to my leg...may save a couple of minutes and your life....perhaps a guide giving instruction needs lots of access or you do when practicing but other than that hopefully you turn it on at the beginning of the day...do a check and then just leave it alone until you turn it off.

I personally have always carried my transceiver in the chest harness.  I almost always wear a lightweight soft shell vest over it even when it’s warm so there’s at least one layer over it. I do carry a phone, generally in a zippered pocket of my ski pants, which I use to run a gps navigation program which works in airplane mode. Occasionally I carry a radio and that would be in my pack. Both radio and phone would be at least 20cm away from the transceiver. In 30 plus years of backcountry skiing I fortunately have never been in an actual avy rescue situation but in practice I finding this system works for me.