Still not clear on the concept

I was getting worried there - we had NO trick-or-treaters for the longest time! We finally got our first bunch around 8:15! On the whole, they've been minding their manners and most had costumes. A few are obviously new at this, though. How can we tell?

1. They yell "trick or treat!" at the closed door, then knock (probably when mom or dad tells them to).
2. They get scared and cling to Mom or Dad when you try to give them candy.
3. They try to walk into the house.
4. They hold up their bucket or bag with one hand and hold out their other hand for more.
   
5. They wish you "Happy Thanksgiving!" (I teased that one, maybe middle-school age, about planning ahead.)