Hi.
I'm in Europe right now about to move back to Canada. One of the things that's common here is that when you get near your prepaid data limit you're sent an automated SMS to notify you of the situation.
In the case of PM, where data is cut off rather than throttled once the limit is reached, this warning would be extremely useful. There is also a business case for it, as you could (and should) remind users of the availability of the appropriate add-ons so they're never without connectivity even if they go over a little.
Even nicer would be to enable the ordering of add-ons through sending a special SMS (such as "USTTD") to a PM shortcode. Here is how my current Swiss provider handles a roaming add-on. Making add-ons more convenient -- do it right from your phone rather than be forced to the self-serve website -- will probably increase sales too.
