Badsnooker player is right, Dan-cat.
Always default to the highest value.
Because of the way the rules are written, they can be difficult to understand.
If you go for the black but pocket the green, it’s a foul shot while going for a ball worth seven points. So foul seven.
If you go for the green but pocket the black, it’s a foul shot while going for a ball worth three points but the value of the ball fouled is worth seven points. So foul seven.
Just to confuse things, though, if you go for a red and miss it completely and the cue-ball hits the pink and then the black, it’s foul six. This is because once the cue-ball has hit the first ball it can do whatever it likes apart from going into a pocket or coming to rest not on the bed of the table or pocketing a ball no on.
In the same scenario, if the black was pocketed, it would be foul seven. There were two fouls here. The first was hitting the pink rather than the red and the second was pocketing a ball not on. The higher value takes precedence.
I hope this is clearer than mud!
Tim Dunkley (World Snooker coach)