Green’s Dictionary of Slang

describing one who is enjoying pleasures for free; taking benefits that one has not earned.

1965		F.J. Hardy Yarns of Billy Borker 145: Joe closes the deal and fills the train with all sorts of mining equipment, beer, wine, food, champagne and a hundred free-loading passengers.
1972		D. Jenkins Semi-Tough 29: There’s never anybody at those things but a bunch of freeloading writers who get high school drunk.
1997		C. Hiaasen Lucky You 185: Greedy freeloading twat!
2000		Observer Rev. 30 Jan. 2: Successive generations of free-loading shits have poisoned that well.