[chrisseaton]

But in British English ‘security to backstage’ would usually be ‘security for backstage’ or ‘backstage security’.

[wyldfire]

I think that US English writers/readers would also find the latter the most common term for that noun phrase. I think the most likely explanation is that the writer+editor(s) did not choose the words well to describe the situation.

[mpclark]

This is a headline, not British English ;)