On recent WestJet flights they announced that you can't use a power bank if there is seat power available, all the flights had seat power except the smallest plane (Dash 8) and that flight was only 18 minutes. They also didn't want any batter powered devices in the overhead compartments.
On the 737s there were only two plugs per 3 seats so not everyone could be plugged in.
On the 737s there were only two plugs per 3 seats so not everyone could be plugged in.