There seems to be a taboo on the restirction of creature comforts such as mobile phones because of the effect it will have on morale. Morale should be treated as a more subtle and complicated subject than this. Without going into a diatribe about the factors influencing morale the fact is that you don't need a mobile phone in the field. They present a multitude of problems not least of which is OPSEC. Ban the carriage of mobile phones on operations - the key is to ensure it is actively enforced for everyone - common hardship rarely effects morale.