I work at a utility company and shared this comment on our internal comms. This was a rather insightful response:

No meter should be clocking backwards regardless of circumstances.

A meter that clocks backwards is faulty and should be replaced. Suppliers wont use your Import reads if they are going backwards. So in most cases a customer will be worse off if you don’t get the faulty meter exchanged as the supplier will estimate their bills based on historical consumption data.

Before smart meters - If you have export capabilities at your property (solar panels etc), you usually had two traditional meters installed. A meter to measure the amount of energy you import from the grid and and a meter to measure the amount of energy exported to the grid. When you generate more than you are using, then that excess energy should only be record on your export meter.

Having a smart meter just means that you have one device, instead of two, which is capable of measuring imported and exported energy. Smart meters can become faulty and clock backwards too.

I think trust is the main customer concern and stories like this one on the BBC don’t help. Although a supplier can put a meter in prepayment mode remotely - they will still need to go through the same procedures as they would do if you did not have a smart meter. They would still need to get a warrant to switch a customer to prepayment, if they owe them money and have not voluntarily agreed to prepayment meters.

Edit: It turns out you no longer need a warrant to switch meters remotely anymore as Ofgem apparently changed the rules.