Yes, if the flight is full... and it frequently is out of LGW, Emirates will get picky about your carry on weight. You may get away with a kilo extra, 3kg over and they'll usually ask you to check it in.
Even when I was Emirates Silver I used to wear a voluminous travel jacket which could happily swallow up a few kilos of cameras, tablets, chargers etc. Once checked in I transferred them to the now slightly overweight carry on bag. I agree it's stupid but avoids difficult conversations with check-in staff simply trying to do their job.