In this question I just saw something that I hadn't seen before and didn't know you could even do. Using a [Tag:xxx] construct the author put actual tags in the question body in addition to those in the Tag section.
Is this something that is allowed (and that I am just ignorant?) or should it be discouraged?
This is an explicit feature, so yes, it is allowed.
You can also refer to tags on Meta with [meta-tag:...]; this too is status-bydesign. The feature is especially useful here on Meta when discussing specific tags.
In this specific case, however, it is just noise and should be edited out. Like over-application bold and italics or using backticks for emphasis, it is still possible to use a feature wrong. I've edited the post to remove the tags, replacing them with backticked keywords (as they are keywords in the API).
