Just some of the things I was able to find with a quick search as I am limited to research right now.
The facts we know are that he was indeed late to meetings or missed them. And that his playing time never suffered for it. JG did fine him once which he stated was protocol for missing meetings.
1.) Mincey then went on to say that tensions in the locker room grew as a result of Hardy’s behavior. Hardy reportedly lost support from his teammates after he missed several meetings and almost missed practice.
“I hate [that] it happened — you talk about a team that was so close knit and tight and all of a sudden it was just different,” Mincey said. “I wouldn’t say that he’s the reason for that happening, but sometimes change, sometimes if it ain’t broke, don’t fix it. You know what I mean? And sometimes with change, the team is different.”
2.)
http://espn.go.com/nfl/story/_/id/14148155/greg-hardy-arrived-late-dallas-cowboys-meetings
3.)
http://www.cbssports.com/nfl/news/report-some-cowboys-soured-on-greg-hardy-by-the-end-of-the-season/
"A few teammates who had supported Hardy early began to sour on him late in the season, in part because his perpetual tardiness for team meetings never resulted in a reduction of playing time. Tardiness was also an issue for Hardy with his previous teams"