In this crime, these things simply may not matter. Again, what I think increases the cost benefit ratio is that bystanders will not accept it and will act in some way. Increase the risk of punishment, then this behavior simply stops as it becomes too costly to engage in it.
At our local community meetings (I live in a rough part of town here in the ATL), the gang task force officers almost uniformly recommend increasing community pressure to increase the likelihood of apprehension and conviction for offenses. That is, once the chance of getting away with the crime declines, offenders are less likely to commit the crime.