I like this idea and added my vote to it.
However, I am not sure if the API checks if a trackable your logging as "discovered in cache XYZ" is still listed in that cache and if it fails if the trackable has moved on or not. Depending on that, this might have an impact whether all logging options are available or not... On the other hand, if that doesn't work, maybe the log towards groundspeak using the API could just be a "discovered log" without specifying any cache but the entry in the table that AddTrackablesAPI then reads could still include the cache. This way Angrentil's request could be fulfilled in any case.
However, I am not sure if the API checks if a trackable your logging as "discovered in cache XYZ" is still listed in that cache and if it fails if the trackable has moved on or not. Depending on that, this might have an impact whether all logging options are available or not... On the other hand, if that doesn't work, maybe the log towards groundspeak using the API could just be a "discovered log" without specifying any cache but the entry in the table that AddTrackablesAPI then reads could still include the cache. This way Angrentil's request could be fulfilled in any case.