Yeah, this one certainly isn't purely encapsulated since group has this intimate knowledge about Windows specific stuff that's not specified in any sort of interface.  It rubs me the wrong way, as does the test I wrote to ensure the delegation when on Windows.... but without breaking apart how things are assembled and introducing something dependency injection like, I basically stuck with the conventions already in place.

I was thinking the same thing wrt to `.respond_to?(:members_insync?)` to at least introduce something that isn't so coupled to Windows, but then backtracked on that idea for the same reason.  But maybe using the duck typing is more appropriate than hardcoding a bunch of Windows checks.  Setting the convention around calling a providers `members_insync?` might not be such a bad thing.

What's the lesser of the two evils here?