Preventing "pushing" topics by deleted answers

Question

There is this old post here which got recently pushed up on the "active" top questions.

On closer inspection, this was only due to a new user adding a new answer. However, the user (presumeably) realized he was answering an old topic, and subsequently (and rightfully) deleted his answer.

However, the questions still remains "top" on the "recently active" list, and I was wondering if this is a bug or should be considered as one. Not only does it "resurrect" old questions, but it also showcases that it is possible to "push" topics in this manner.

To "push" a question, simply add an answer and then delete it.
The question will move to the top of the list and shows a "modified by" entry, despite the answer being deleted (and the change invisible to many users.)

Just did it here on the main site:

Somehow, I believe, such practice should not be possible by the system and "deleted" posts should also be ignored in the recent changes, should it not?

Answer 1

I think that this may be best left to moderation as it is more of a user issue than a site-design issue.

Adding an answer to a new question and having it appear at the top can be important, as it may be a correct answer to a question that has been looking for one, but was long pushed off.

As for it sticking around when the answer is deleted -- While the answer is in a deleted state, users with a higher rep can see the deleted answers and it should become apparent if a user is continuously doing this just to bump questions.

As for the modified by: I have an issue with this, in general, because it confusingly looks as though other people have modified the question when, in fact, they didn't do so. This is a UX design issue with SE in general, though, in my opinion.