Yes, I have cheated and plagiarized on several occasions without getting caught. I have also helped others cheat on several occasions. In one instance, it was for money. The person was working full time, was not interested in the material, was only taking the class for a liberal arts requirement and could not have done the work- or at least not very well. She offered me money since I was one of the best in the class. I wrote the papers for her but later tried to refuse to take the cash. She convinced me to take it in the end, though. I'm not proud of it but there it is.
I also know of at least one person- my best friend- who semi regularly buys papers from an online service. She's never been caught and is actually very blase about it. She fully
expects to get away with it Scot-free. And she has, for years. She says that her sister also does it but at another place.
Our professors thunder about academic dishonesty at the start of every class. The syllabus always has two or three pages on it alone. The college makes it very, very clear that it is not tolerated and that the consequences are
very bad. And yet almost every single one of my professors, past and present, claims that they typically get
several cases of plagiarism every semester. A lot of them say "There's at least one every single class- and they always get caught." It's just unavoidable. Always happens. Kids just do it.
ETA: I also know of a case of a woman (a former friend of mine) paying her roommate (a good acquaintance of mine) 200 dollars or so to take an exam in Polish for her- and threw a yoga mat and some free yoga classes into the deal, too.

It was one of those tests that exempt you from the college's language requirement. The cheater knew Polish fairly well because she was half-Polish- but was utterly clueless about the grammar and things like that- but the roommate was a recent immigrant from Poland. Of course, she passed with flying colors- and had the fairly good luck to not get caught, despite the fact that she looked nothing like her roommate (she showed the cheater's ID as her own and was waved in by an inattentive test administrator) and was wearing a cheap blonde wig on her head (if memory serves).
You would think most people would stop there. You'd think. You'd think that would be enough for most people. You'd think. You'd think they would count their lucky stars it worked out once and never try a stunt like that again. You'd be wrong. This woman then had the
gall to call
me and ask
me if I knew anyone at
my college who "Is
really good and
really smart at history or literature or psychology and has blonde hair and is tall like me so that they could take the test for me. Could you keep a lookout for someone like that for me?".
Yes, she wanted to exempt herself from
more classes. Getting away once wasn't enough for her.
I rather coldly responded "I could ask around but I can't really think of anyone like that. I might ask them- but I'm not promising anything. Maybe."
Translation: "WHEN HELL FREEZES OVER!"
Does anyone want to guess what this woman was studying to be?
A child educator.