Any reason for not allowing "weak" keyword in protocol?

[Paka (J)]

Ownership on protocol property requirements

Sent from my iPhone I can understand that, I am just wary of "let's do a partially detrimental change The key here is that there is no detriment to this change. There's no functionality that's being removed, only misleading syntax. Why is it misleading? Because it is not enforced, but protocol extension default methods being shadowable but not overridable and presenting no warning is a very similar issue... if the answer is the same there (at least for classes), I am more than happy to get…

I read this post but can't figure out exact reason for not allowing to use ownership keywords in protocol declaration. (especially for "weak" keyword in AnyObject protocol)

Does anyone know?