Actually, quite the opposite. Whenever I fly US or Canadian airlines, I am well, not horrified, but concerned how blatant cell phone use (for voice comms) is ignored by the FAs well after the 'phones off' message is given; including for new calls dialled out. I assume they turn a blind eye for fear of alienating business pax.

While having my doubts about what actual 'damage' the phones may have until actually rolling to take-off, I wonder at what other rules the FAs are ignoring or not enforcing and the culture of the airline given over in its crew training.

On Asian/Pacific airlines such as SQ, QF, DJ and NZ, after a small tolerance period after the announcement, especially for J pax, phone users are mostly politely and variably firmly asked to turn off. Yes, exceptions do occur, but rare in my experience.