Stuart
As a general rule, once you pay the bar fine you are free to stay in the bar, or scome and go as you please. I would have thoght in most cases the bar would prefer you to stay and buy more drinks.
The only thing is, most bars will charge you for a lady drink rather than the regular price, should you buy your LB further drinks.
Actually kliome, I dont think what you say is quite accurate.

Once you have paid the bar fine the girl "has left work". As such she is no longer entitled to ladydrinks as work has finished. My advice to people who stay on in a bar with a girl that they have already paid the bar fine for, is to tell the girl and the cashier that its drinks at normal prices now. Check your bills as you receive them and querrie any that are ladydrink prices and send them back for a new bill. Charging Ladydrink prices for a bar fined girl is a scam.
Useful thai- buy-sir- give - high- drinks - durm- normal- tamadar
buy give drink normal
Try - sir high durm tamadar
Not only do you save money but you learn Thai aswell.

PJA aka Somchai