What can be done to protect children from school shootings immediately?

@SW-User Getting out of a country is easy. Moving permanently to another that is better for you is less so. You generally need a residence permit. To get that you either have to have a job, for which you need a work permit, or you have to take a large sum of money with you. These are insurmountable barriers for many people who don't have skills or qualifications that are in demand in the destination country.

And if you are a US citizen you have the added complication of the IRS chasing you for tax even if you are no longer a resident of the US.