There is new update in Robbing, Mafia Wars, that you can use Burner, to Call for Back Up.
Robbing Calling for Back up
And Burner is like this
The Burner Mafia Wars Robbing.
When you fail in robbing, Fail in Robbing Mafia Wars, use Burner.

But there is no guarantee that you will succes robbing,
Still Fail in Robbing

Call For Backup will provide a boost of attack from a Top Mafia member to help you defeat your opponent and rob their properties.
Increasing your Robbing Mastery level will up the maximum number of Burners you can possess.  So, all of you know, my robbing mastery still level 2. Look at first screenshoot, Zynga just give me 2 Burner.