Mobile phones: Charging

[AngloScot]

When i put my mobile on charge, it changes from 'ring & vibrate' to 'loud'. Why does the phone not want to vibrate when it is being charged?

[ian.miller]

Because it assumes you wouldn't be charging it in your pocket?

[tomd]

The charger might fall out, or it might be charging in a desk charger (if it's a basic type charger the phone won't be able to tell the difference).