By the way, I have only one curious question that: What happen if I the quote button to quote your post, for example, but during my time to compose my post to answer you I mis-delete the end bracket? Is this considered as plagiarism if someone else use bot to find plagiarised posts and report such posts?
It may very well be
reported as plagiarism, by a user or a bot, but I would think you would be very unlikely to be banned for it. If it is quite obviously supposed to be a quote, and you have just messed up the BB code, I'm sure the moderators would realize that and not issue a ban. I'm sure I remember this exact scenario being discussed in a meta thread a while ago.