I've posted this in the past but take your awning rod. Walk to the rear of the awning take the awning rod and place the rod into the hole in the awning roller. Let the rod hang down next to the awning leg now take a lenght of rope 1/4" is fine. Run the rope through the loop in the awning rod and then through the hole in the foot of the awning leg, tie the ends together pulling the rope tight. You have now made a free awning roller lock.
The problem you had happens when the roller latch gets worn and won't lock the roller tube. A quartering wind on the side of the RV will cause the awning to unroll, your lucky you didn't loose the awning.
When you get home re-bend the awning rod so more of the rod sticks into the roller tube hole. I take a bungee cord and put it around the awning rod and awning leg just to keep it from rattling.
Tying the awning legs does no good as the awning can still unroll with the legs tied together. You have to stop the roller from moving.