There's pretty much no information available about the effectiveness of putting phones in rice.
Effectiveness of bumpers depends on the specific phone and the specific bumper. Pre-iphone5 iphones are incredibly fragile, polycarbonate bodies like the higher end Lumia phones and cheap plastic feature phones tend to be the most resistant to damage. Thin bumpers don't provide much protection. Thick cases provide more protection.
Effectiveness of bumpers depends on the specific phone and the specific bumper. Pre-iphone5 iphones are incredibly fragile, polycarbonate bodies like the higher end Lumia phones and cheap plastic feature phones tend to be the most resistant to damage. Thin bumpers don't provide much protection. Thick cases provide more protection.