When Jon fights off the other three trainees defending Sam, one of them says that he yields, while holding his sword. In the exact next shot, his sword is on the ground several feet away from him, without sufficient time to drop it.
During the joust between Ser Gregor Clegane and Ser Hugh of the Vale, they pass each other (Clegane delivers a glancing blow) and then round the fence to joust again. As Ser Hugh rounds the fence, his lance is conspicuously missing from his hands, only to reappear in the next shot as he lines up for the next (fatal) pass.
Knights fully armored for jousting weighed close to 200 kg (400 lbs). A man the size of Gregor "the Mountain" Clegane would weigh even more than that. The horses shown in the tournament would simply collapse under such weight. Armored knights (e.g. in Europe) used MUCH larger horses.
After a knight is killed at the tournament, he is seen being easily dragged away by two average sized men. Mounted knights at tournaments wear the heaviest armor. Fully dressed, he should weigh close to 200 kg (around 400 lbs) - not something that can be easily dragged through the sand by just two people.
In Bran's dream, he is about to shoot at a target, when the three-eyed crow flies across. We see in closeup that the forefinger of his shooting glove is twisted under the bowstring, which would spoil the loose.
Knights in jousting tournaments rode on the right side of the railing, not the left. This was to make sure that their armor was able to receive the brunt of the lance hit. The riders would reach the lances across their body and over the railing. The means by which knights jousted has nothing to do with why traffic in England is on the left side of the road. Traffic is on the left side because how armed men would pass each other in feudal societies.