Hi,
There is no chaos because of this, the chaos remains in any case no matter what you know about what´s installed out there. And in any case, it´s still an assumption to think that because a site upgraded the bdii package it also upgraded the glue-schema package. Maybe a fair assumption, but an assumption after all.
I think we need a clear way to see which BDIIs supposedly support the use of GLUE 2.1. Else we may run into nasty operational issues, where things sometimes work and sometimes do not, while at the same time all BDIIs present themselves as equal... That would be a _disservice_ to the user communities and their support infrastructures. Since only the BDII version is published today, the easiest way is to increase its version number, unfortunately. At the same time we may want to consider publishing the schema version explicitly.