Looking through my notes from the Mobile Payments Forum last week (post here), I came across this tidbit mentioned by several speakers:

One thing you should do right away is capture mobile phone number(s) in your customer information system.

Not only does this provide a marketing database for people to contact when you introduce mobile services (note 1), it provides an alternative number for account problems now.

You should add the fields to your online banking My Account area and also begin asking for it on account signup forms and loan applications. While you are at it, seek permission to send a text message(s) when new mobile services are launched.

Note:

1. We are not suggesting you telemarket to the mobile numbers; that's a bad idea. But you should contact these customers through normal channels (email, mail) when mobile options become available. Also, seek permission to send a text message(s) to inform users of new mobile options.