The prior article on Casting Crowns noted they gave a concert at an “undisclosed location” to US troops.  A CNN article indicates they did a “three-night swing through Kuwait and Qatar.”

The linked video at American Forces Network indicated the group played to US Army Soldiers as part of their Comprehensive Soldier Fitness Program.

Also of note: 

With the chaplains sponsoring the tour, the group was faced with the decision – pay for it themselves or don’t go. It was definitely worth it to pay, Hall said.

Hall lauded the chaplains, saying they did most of the work setting everything up and making all the arrangements.

The Christian group apparently wasn’t sponsored by the USO or by the military itself (as, for example, Kid Rock was).  They paid their own way to support the packed houses of troops to whom they played.

Also at the Army Chaplaincy blog.