You should be very, very concerned.
As a survivor of Benchmark, I tell you that what you need to worry about is not the impact of the young people on your neighborhood - most of them are just lost.
What you should worry about is the for-profit, under-qualified and abusive way that the program is run. I, and many other survivors of Benchmark, continue to receive therapy in order to recover from the damage inflicted BY the program.
As a side note, having seem the absolutely OFFENSIVE comments Benchmark issued comparing your community members to Nazi's, I would mention that as a Jewish resident I observed continuous ignorance and prejudice against myself and the few other Jewish students. That is not to mention the literally fascist ways that Benchmark itself operates (having students dig and fill in ditches all day in the heat, placing them under house confinement, restricting food intake...). Pots and kettles, anyone?
Don't let them into your neighborhood. Be a good person, find an organization that does REAL GOOD and invite them to come into your town - not these money-grubbing and abusive vipers.