Make sure you have a life jacket with you.

[Bean]

It depends.  What are the wind and current conditions? How far did the board go? How shallow is the reef?  The shoreline could even be a factor.

If the board is retrievable, but a long swim you will be better off leaving your paddle and swimming for your board.  If you throw it like a javelin out past the breakers it might still be there when you paddle back out.  Of course if you have a paddle loop on your shorts you're good to go. 

[photofr]

I have watched students 100s of times when presented with different scenarios: the point is that it makes them think, it made you think about it, and it would make anyone start thinking.

Education is ... "start to think about it".

The law is... "its the law... and I won't think about it".