How about having off-peak hours surfing? I think that is the best way to prevent the network being inaccessible during peak-hours. For example, from 11 PM or 12 AM up until 6 AM or 7 AM there will be no data capping. That technique is being used by the Consumable Plans of SkyCable. They may have a monthly bandwidth limit (since it's consumable duh) yet they have off-peak hours surfing and downloading.