This is similar to the problem we had with Starcraft versus Starcraft 2. I believe my answer to that one still applies here.
There is a clear distinction - one has an I, the other has an E. Reading comprehension is essential to writing a good answer, so it's not really the tag's fault that people are posting the wrong set of answers.
If someone answers a question about Minicraft with information about Minecraft, they are the ones who are in the wrong. Comment them to inform them of their mishap, even go as far as to downvote them. Their answers are indeed noise to you, and they are unhelpful to solving the problem you have. It'll teach them to actually pay attention and read the question clearly in the future. If this trend works out enough, enough people will learn to stop doing stupid and the problem will be solved.
As for disclaimers, I'll quote myself from the previous question:
While it sometimes will help to add a notice explaining which game you are referring to, this is ultimately redundant noise as the game you're talking about should already be clearly established by your question body and tags.
I think the best solution, thus, is to make sure you're clear in your own writing. As long as you're not saying things about the other game whose name is similar, anyone who answers about the wrong game is making their own mistake. Then, when they do make those mistakes, make it clear, painfully if you must, that they're not reading your question. They'll probably delete their answers over time, or otherwise suffer for it, so the end result is that you'll get rid of those off-topic answers.
ludum-dare-minicraft
? Awkward but I'm not sure what else would work.