Because nobody has answered in one of the both threads below, I start a new one.
I wanted to try this myself because I had the same case as Loaden described many times in other projects. That's why I thought it is useful. However, for menus I usually define my own ID's and do not let them have auto-generated. If I got you right that this would be changed on the fly which is of course not what's intended. However, if I set an ID to be a member I usually explicitly want to use the ID. If it is
not set to "member" then I personally do not use it at all. That's why the concept of Loaden's patch works well for me.
However, I see the point when it would not work and in fact changing "is member" multiple times is not what I did and if it causes hassle that that's not what we want.
So I would agree to filter by type, but would suggest to leave the types as an option, including "all" and "none". That would provide most flexibility, but also causes most change (I know).