The Hawk-Eye goal line technology has got absolutely nothing to do with Sky, it would have its own picture feeds and would send a message to the ref within half a second of the ball crossing the line. Sky (or whoever) might take a data feed from Hawk-Eye to show as part of their coverage, but they'd have nothing to do with any decisions.
Hmmm, not convinced. I believe what you say, however, greater use of cameras, games shown on Sky...I'm not saying Sky would alter decisions, but they could influence them, given the money they put in. What's the betting that at some point in the future Sky offer to pay for it in Premier League grounds?