There is a lot of good posts in this thread.
This is really simple. Hester had 3 options
1) Walk away and let the guy get away with no repercussions
2) Fight the guy and risk getting in trouble and losing hundreds of thousands of dollars and probably wind up in more trouble then guy who originally slapped him
3) Tell the casino security
Which option would you choose given the 3? The answers easy for me.
And to reiterate, snitching is when you tell on someone to get a lighter sentence for yourself; particularly someone you did dirt with.