2. Yea? Tyrion got Shae's chain on? Awsome.
1. I know that sigals exist, but... When i watch HBO with my friends they ask mad questions "whos this, whos that" it would be easier to just say the animal that relates to the people. e.g. knight of flowers, the hound (HBO did a good job with that), etc,etc. My friends know that the Wolf is Stark, because they have wolves, but it would be simpler to have Jorah and the old bear both have a bear on there chest.
When Cat arrests Tyrion she is like "Is that the sigil bat of Harrenhal on your chest?" Then the knight gets up, and nothing is on his chest...
They tried... It says right there. Either it didn't look right or it was too uncomfortable for the actors.
Everybody wearing sigils all the time would look stupid. Especially for people in the Nights Watch. I can see the rest of them wearing sigils to very formal occations or to battle.
Also, the maesters do wear chains in season 1.