I would urge you to look closely at this recent successful global ban: Requests for comment/Global ban request for Messina
Especially the closure, and (if I may be so bold) my own comment (Support #5). In short, this appears to be a case where the ban was needed and worthwhile; and yet, it was not covered by the Global Bans policy. It fell short on requirement #3: none of the wikis referenced had a clearly documented, community-endorsed ban or indef block in place.
I believe the deeper issue is that these wikis (German Wikipedia and Commons) simply lack banning policies, and therefore processes. Perhaps they have gotten by fine without them to date; but I believe if we are to have global bans at all, and rely on local sites when deciding about them, we need clearer documentation.
- @Peteforsyth: If I am not mistaken, German Wikipedia does have a community-based block process (de:Wikipedia:Benutzersperrung), but I don't speak german. As for commons, there's no policy, like in the vast majority of projects. None of the Spanish projects have banning policies for example, but that does not mean you can circunvent any blocks imposed there. I'd add too that I miss a time frame in the policy regarding how global ban discussions should stay open. IMHO 15 days max. would be very reasonable. —MarcoAurelio 09:26, 21 January 2016 (UTC)