My personal experience on plagiarism was more of our research group catching each other while writing out our review of related literature- we all read and reread our drafts and our sources, so we were able to edit and place quotation marks and citations as appropriate.
My other personal experience was more of an honest mistake of placing an intext citation without the full citation in the list of sources at the end of the manuscript. This was pointed out by the reviewers when we turned in the manuscript for publication. That was embarrassing, and I'm just grateful that it was pointed out.