This headline is a classic example of journalistic language abuse:
Today’s ATT outage is just a preview of what can happen when cell service goes out.
No. Cell service going out is what happens when cell service goes out.
It’s a tautology, like Three = 3.
Treating it as a warning of a potential trouble turns a tautology into a COMMAND. The headline says in effect, If you don’t follow our ORDERS, something awful might happen, which fortunately didn’t happen yet.
Polistra's Mill 