They should purchase more SIM cards to create more accounts
In some countries its actually really easy to get ahold of a SIM card. I'm from Malaysia and when I go there I can get a throwaway SIM card from any convenience store in about 10 minutes for a couple bucks
EDIT: Meanwhile in Canada.... :rage1:
They're free in the UK, but need an initial top up to activate, £1 would do this on some networks.