I have 6 grandchildren in summer camp in Penn. They are divided into 2 camps.When we used to go up on visiting day to visit, at the end of the road was a small shack with a senior citzen with a radio and cell phone.
In normal times this would be adequate to keep out unwanted individuals.However these are not normal times.As I look at the carnage from Norway,you realize that the crazies are all over.Copy-cat murderers are always the norm.
If this is an Islamic terror attack, they will consider it a huge sucess what with all the publicity,and the destruction.
Norway I believe was one of the first to recognize Hamas!
I believe American summer camps-especially Jewish/orthodox will have to evaluate 24 hour security.For what they charge per child they can add that to their budget.
There may be Federal grants available for that purpose.