Sameness for fresh clones

Would it make sense to add to the doc of Data::same that the following property is recommended (or even required)?

assert!(x.same(&x.clone()))

I'm asking because there were some confusion about how to implement Data::same for im::Vector in https://github.com/bodil/im-rs/issues/117 and https://github.com/bodil/im-rs/issues/129. The current doc of Data::same would even allow the following implementation.

impl Data for Foo {
    fn same(&self, _other: &Self) -> bool {
        false
    }
}