Terrific! That would be as easy as making a watch waterproof! They could just include more plastic blockage certain places where if it gets in it could damage the tamagotchi. Then everyone will be happy!
And if they're relying on people breaking them for some percent of the money, then they can sell Tamagotchi safety cases, with a lanyard and a shorter strap, like to put around your wrist. Then there is no loss! And they could make cute patterns, too! How adorable!!!