If you don't want the library to be loaded without dependency then maybe include/or not the library within your addon's folder BUT don't load it from your addon's txt file but let it have it's own librray's txt file and use the DependsOn in your addon's txt file.
This way you provide the lib and your addon should work as expected and NOT load if the lib is missing/get's removed.
Adding additional code is curently only needed for the phase where libraries might exist as version with and w/o LibStub.
My approach would be to remove LibStub completely and let addons crash so they need an update but this will break older unmaintained addons as well and thus is not the wanted behaviour (I wouldn't mind as it's easy to ask and fix them as well but some ppl here just want everything to be running smooth and fine. Remembering the wide user reactions on the library changes in the past I can understand them... Not all of the users seem to wish to get a fix but love to simply complain and rage
)