I consulted my dictionary, and found that “cowboy” as a noun means “someone who is dishonest in business, or who produces very bad quality work.” This phrase is interesting. Is it used outside the U.K. too?
http://twitter.com/Sannet1
“Overheard last Monday at my local Sainsbury’s petrol station: I cowboyed it a bit! #themindboggles”
I hope that cowboys are not angry about my posting. 
This cowboy isn’t, I can’t speak for others, mind! I found it interesting how the noun had been used as a verb. Monday was the first time I ever heard it (and I worry about what you can ‘cowboy’ at a petrol station: the mind really boggles. No, it wasn’t a BP-owned petrol station!