As I said, I've never seen it create a problem, but the chances of two people with laptops in a two-seat prime row (exit/bulkhead/whatever, reserved for elites/full fare) are far from "slim." I've often been in one of those when both my seatmate and I had laptops. Add in DVD players and all the other stuff one might want to plug into a power port and it gets potentially worse.

Your odds are better in a three-seat row, of course. In a five-seat row such as the center section of a 777, the odds of all five wanting to use a port are negligible.