Oh I know. Even though he is tying her up she isn't threatened at all, she's just annoyed.On her face you can practically read that she is thinking something along the lines of "Stupid little brother doing stupid little brother things."
In contrast with Liza in the scene with the box under the bed she tries to hide it with anger but she is immediately in full blow panic mode.
That is one of the things I always liked most about BBS and something rainces did really well. Even though Bobby basically wants the same thing from all of the girls, his relationship with them and therefore his approach to all of them is completely different.
But to come back to the Lucy scene. If you want a more cooperative Lucy maybe it helps to remember why Lucy is letting Bobby tie her up.
Lucy first let Bobby spank her because Bobby lend her money and when he asked her to pay him back she wouldn't or couldn't pay. (She says she doesn't have the money but she doesn't appear to make any effort get money to pay him back so it makes no difference) For Lucy while she doesn't like to get spanked it's apparently preferable to actually coughing up the money.
Since the tying scene started the same way maybe go done some kind of dept forgiveness route.
Bobby finishes tying her legs and says he will forgive 20$ of her dept. If she lets him tie her wirst he will forgive another 20, blindfold her another 20 and so on.
