First time we ever had this enforced was last week at GRU, connecting from a Delta flight, in biz class, from the U.S. to a Gol domestic flight. At the GRU transit desk, after our checked bags had been processed (and at the 70 lb. per bag allowance for international flights), the Gol rep asked to weigh our carry-on bags and would not issue our boarding passes until we got them down in weight (there had been no limit on Delta). She said the allowance was 5 kg-- the same as for a strictly domestic itinerary-- even though we were transferring from an international flight (even though the allowance was higher for checked bags).

We had to get our checked bags sent back from the baggage area, to where they had gone by conveyor belt, and put into them items from our carry-on bags. Gol rep allowed us to proceed when they weight showed about 6 kg.

We had flown from Brazil to the U.S. and back. When we took our first flight, a Gol domestic flight to connect with Delta at GRU, there was absolutely no question about carry-on bag weight.

On board the flight, Gol charged for everything but regular water. Even coffee (instant!), soda or chips. I heard TAM is still giving free snacks, though not a meal, on domestic flights, but can't confirm that.