This cached file is the equivalent of the local file that is created when working with a central file located on a traditional file server. When you open your project through the Autodesk Docs > Project Files>..., you're just overwriting your local cached file. I'd just want to be sure that at the end of the day, you sync to central, so at least all of the work you've done up to that point has been synced. So, the only risk I'd say that you run is that upon opening the next work session, your local cached file might end up not being compatible with the ACC version, for whatever reason (someone deleted the central and made a new one or something along those lines); in that case you'll get that error. In that case, obviously go through the regular Autodesk Docs dialogue.
Like you said, because the files are employing GUIDs rather than a set path, if the GUID changes, then you won't be able to load the model at all. Just remember that if a model is moved (into an archived folder or something), the GUID does not change, so it will just follow the new path; in that case you might end up doing work on an archived model, in error.
I DOUBT this method is documented anywhere, otherwise you wouldn't have come to the forum!
That being said, because you would be deviating from the recommended and documented way of opening the file, it's not "technically" accommodated for. Fortunately, backup versions and published versions exist in case something DOES happen.
