As a publicly released member of the Spring portfolio, it's inappropriate for new features that are considered "for consideration by the public" to be added to the production modules (i.e. core, execution, samples, etc).

A formal "beta" branch should be established or an Apache-style "sandbox" module should be created to appropriately compartmentalize code that is in RFC-like status but believed to be stable (as opposed to the dev / snapshot branches which may not be stable at any given moment).

Using "samples" as a de-facto sandbox seems wrong.