It is not acceptable for anyone to say that it is their own work when they didn't even type one word of it
Credit and permission from the original writter should be gotten before submiting anything that was not written by them.
If permission is denied then it should not be submitted reguardless of how well written it is. and I consider this to be acceptable

when they use it as a guide to help them over the rough spots or when they have writers block . and the amount
of warez that are being traded doesn't not make it right to say I wrote this when it wasn't. and I also I wonder
how they would feel if they spent hours writing something that they were proud of and then someone came along
and copied and pasted it and said they wrote it, I know I would be pissed if that happened to me. so they shouldn't do it to other people