Add my two satoshi...

Plagiarism is always intentional and simply cannot occur by mistake. However, in my opinion, there are two types of plagiarism namely conscious copypasting and unconscious one. The first definition means a person knows what is going on, he steals someone else's work and never gives credit to the original author. Unconscious plagiarism is also intentional, but the difference is a person takes someone else's work and never gives credit not because of bad intentions but forgetfulness, carelessness, or, in some cases, due to lack of knowledge of how to correctly highlight someone else's message. The problem is it is almost infeasible to figure out whether a person had bad intentions or not, was it conscious plagiarism or temporary stupidity.