El Nino is of course exactly correct and quoted the relevant rule verbatim. As he said:
"Simply stated It is a foul."
Sorry Sickpotter, you are incorrect on this one.
It is simple really.....if you NOMINATE a ball, you MUST hit that ball first. Just like when you pot a red, then two colours are near to each other so obviously, you nominate one of those colours then you must hit the nominated colour or it is a foul.
Same thing...you NOMINATE the free ball, therefore, you MUST hit the nominated free ball first to be a fair stroke. Even if you hit the "natural" ball first, it is still a foul because you did not hit the ball you nominated.
As for simultaneous hits, they are a special circumstance, but actual simultaneous hits nearly never occur. If one observes closely (as a professional referee does), then one will be able to discern that one ball is struck first in 99.999 percent of cases. But there is a rule for that 0.001 percent and it is also quite easy to understand...
If you are playing at a ball on and strike simultaneously with another ball which is not on (such as if you are playing at Black and you strike Black and Red simultaneously), it is a foul. On the other hand, if you are playing at a ball on and strike simultaneously with another ball on (such as striking two Reds simultaneously), there is no foul. So it follows that if you nominate a free ball and you strike simultaneously with another ball on (in the original scenario, if the Brown free ball and the Yellow were struck simultaneously), then there is no foul.
You might wonder, then why is Yellow even considered to be a ball on if you are not allowed to strike it first? Remember simply....if you NOMINATE a ball in any circumstance, then you are obligated to strike that ball FIRST. Yellow is still considered to be a ball on even though you cannot strike it first after nominating Brown because if the Yellow happens to fall in the pocket on the stroke, it is a fair stroke and points scored because Yellow is still a ball on despite the Brown free ball nomination.
If SIMULTANEOUS HIT situations seem confusing, don't worry about it. You are not alone. Simultaneous hits almost never occur so don't lose any sleep over the unique rules required for them.
P.S. to this- There is a famous "simultaneous hit" controversy that everyone probably already knows about. You can find it here:https://www.youtube.com/watch?v=sMif__71FuQ
This is possibly the only RECORDED shot in the history of Snooker on video that might legitimately be called a "simultaneous hit", the dreaded 0.001 percent. Personally, I think the ref got it wrong in absolutely trying to call that it struck first one way or the other. Since the Rules allow for a simultaneous hit, he should have ruled it as a simultaneous hit and called foul.