BB:Not free leccy, but leccy paid for by the rest of us.
An interesting academic point which I have been trying to get my mind round.
Pre competiton days,such non billings got caught up the calculation of each companies line loss factor.This was a measurement of the difference between units purchased and units sold.Part of that,as I recall,were distribution losses,i.e. the units lost through the network system during distribution. Each company had an accepted line loss factor agreed under the regulatory price controls. Provided the companies performance was in line with these factors then I think you are right that we all paid the price for that.
Now,due to 'so called' price competiton,I suppose that any underbilling by a company goes straight to their own bottom line. To that extent,I think,and happy to be corrected,that the ghost customers are benefitting directly at the expense of their supplier,whoever that is within the system.
The good news for the customer's concerned is that as,Conmankiller states,that any backbilling is limited to two years currently and soon to be one.
As the fragmentation of the billing cycle processes has occurred with different companies reading meters,then there is less and less incentive and possibility for these issues to be picked up by a diligent meter reader.