I dislike this, but I will adapt to it. I intensely resent being forced to own a mobile phone by society in general, and was strong-armed into by my bank two or three years back (they said they would simply refuse to validate certain online purchases unless I gave them a mobile phone number. I had used a land line number for years up till then, and it had worked perfectly well. Anyway, that's by the by…). I had held out against the aggressive hysteria of friends and family for years, saying to them, “Just fucking phone me on my land line, for fuck's sake! if I'm not in, leave a message, I swear I'll get back to you!!”
But has anyone at the club considered that a mobile phone is well worth stealing? Some of the most sophisticated ones are worth hundreds of pounds. I think the absolute top of the range one is worth not far short of a grand.
A plastic seasoncard is not worth picking anyone's pocket for, unless you happen to be a City fan yourself. And even then, it could just be cancelled really rapidly as soon as the owner found that it had gone missing.