- I would argue that these tags have no difference in meaning (this thread has a +9/-1 score),
- scanning has no wiki, while scanner does,
- the tag synonym suggestion mechanism is fundamentally broken on smaller sites
I have created a suggested synonym. Anybody* who agrees with the suggestion can vote for it, anybody who doesn't can vote against it.
This may seem long-winded (especially with consensus a few years ago) but this is the way synonyms are supposed to be made these days, not moderators pushing everything through on very light opinion.
* This isn't open to everybody, there are rules:
Users with a total answer score (total upvotes minus total downvotes) of 5 or more on the tag, can vote for tag synonyms. Suggestions will be automatically approved when they reach a score of 4, and automatically deleted when they reach a score of -2.