Just now I saw
this question and this question two questions which are deleted afterwards, which appears to be copied exactly from another existing question, and surprisingly some "users" also answered exactly like the question they are copied from, and they all get upvoted.
Therefore, I believe they are actually spammers and flagged the questions.
If these questions are indeed by spammers, shouldn't it be reasonable for the system to detect this kind of question as exact copy and blocked automatically?
P.S. The reason I notice the two questions is that one of them appeared on the "hot questions" list, and when I view it it feels really strange due to the answers (including low-quality ones) getting same amount of upvotes, that's when I finally realize that it is an exact copy.
I feel that I found the situation due to being lucky. But what worries me is that the system didn't catch them automatically.
2013-06-19: This question on bricks.se seems to be having the same situation. Again, discovered on the "hot question" list.