I know what "Black Friday" is and how the phrase first came about. What I would like to know is how the phrase evolved into "Black & blue Friday" which seems to have come about in very recent years.
Although I can make a guess, I have not found any clear cut explanation. My guess is that the phrase slipped from black that depicts the crowds of people in the shops and streets on that particular Friday to black & blue to depict the bruises shoppers get from jostling in the heavy crowds.
First question: is my guess good? If not why do people say Black & blue Friday?
Second question: when (and how/where, if anyone knows) did the phrase first appear?