Yes, this is a no brainer. They can't get the money from you to replace a screen for $200, if it's protected.
And with the Otter cases, the water detector probably won't change, so there goes another $200. Money, Money, Money.
Math fail. Aside from the fact that no one has ever saved their screen using a screen protector, they make a lot more money selling useless protectors than they will on replacement screens.