I could TOTALLY use an API into UM that would allow me to annotate objects, whether from WFA or elsewhere. WOW would that be useful. I've been asking for this and waiting on it ever since UM 6.0. PLEASE add this API!
I am about to start using WFA in a big way, and this was one of the primary applications I was going to use - ensuring that specific annotations are added to each volume that's created (and in some cases that they are changed when resized). It didn't occur to me that this might not be built-in as a feature already. If it's not, then include my vote for adding it!