We carry some tags around which are frequently misused, despite their usage guidance messages, e.g. raspberry-pi-foundation:
The Raspberry Pi Foundation created the Raspberry Pi. Please, DO NOT use this tag just because it is something to do with one of their products, the entire site is about that anyway!
Luckily there is a feature to help the users guide to a proper use tags: tag warnings (follow link for the look&feel). The warning will pop up when entered into the question and that would be the final moment to give some advice how to or how not to use it. See this example.
So this is not so much a question about whether to implement it or not, but a collection of proplematic tags and appropriate tag warnings to go with them.
We'll collect them for a while and trigger a community manager to set them up when ready. Feel free to add new tags (one tag per answer), make your answer community wiki to help easy editing, and please propose changes to the tag warning messages.
Deadline for contribution to that matter: March, 31st
Please note that we, the users and admins of Raspberrypi.Stackexchange cannot make the necessary changes. We need to have a community manager do it. It would be advisable to hand in all relevant tag/warning combinations together. So please do not hesitate to make suggestions now.