aeh speaks truth, to which I'll add: one of the hazards of playing with much older people is that the adult can take what the kid dishes out, and may not be providing sufficient feedback. The child can play with excessive aggression with the adult, then bring that same mode of play to peers and younger.
I've seen one dad whose idea of rough play was to allow his son to grab him by the hair and beard and pull him off the couch. I've seen another whose rough play oftentimes turned into the kind of dominance-establishing mentioned at the end of the article between them, and it stopped being fun. I'd categorize both dads as having failed to establish proper boundaries at opposite ends of the spectrum.
