current implementation brakes Magento modular structure. Module wishlist shouldn't be dependant on cataloginventory module, and shouldn't know anything about it's config options and implementation. All logic of checking values set by cataloginventory should be located at cataloginventory module.

Use observer pattern to implement this low-coupling.

I understand, that there are few similar checks of cataloginventory config values at wishlist module, but it's bad practice. Don't follow it.