When the girl almost gets killed in the car wash, the moment before she is looking at her Nokia phone, and concludes she has no signal.

When a Nokia Symbian phone has no signal, its says no network, and shows now bars on the signal meter.

In the movie the signal bar has a black cross, and it says "offline" at the profile status. This means the creators put it at flight mode themselves, and its not out off signal.

Never hears of GSM jammers to create a real "no-signal" effect? :)