My first instinct is to say that the issue you brought up (others using the tag simply to gain our views)is a "future us" problem, mainly because I doubt it will ever become that prevalent.
However, that is also a lazy answer and, while I have been known to use them, I'm trying to use them less.
So, downvoting seems like a bad idea (as explained by @lextenebris), so let's consider that out.
Ignoring is always a thing to do, but will that be effective? Probably not. Regardless, it will still take up "viewable real estate" and time (looking at the content, trying to find any revelant information).
Hmm. Will keep thinking on it.
In theory, the advent of some sort of Community architecture on Steemit will help the development of communities out a lot. Of course, figuring out when that is actually likely to happen and how to make use of it is an entirely different issue.
The proposed mechanical changes to Steemit are – interesting, but not sufficient to the purpose, in my opinion.
Still, worrying about tag pollution before a tag actually exists in any number to be polluted is making a lot of assumption, which I'm not really down to do.
That argument is deployable against doing anything that someone hasn't done before. As such, I have to dismiss it out of hand as ridiculous.