HELP !!!!! how to tell if a pre-paid electric meter is being hotwired?

If all the seals are in place then its impossible to have been tampered with.It is possible for her meter to be out of calibration which could account for the high cost,but then it could also be her use age,i.e she may have left her immersion on(very common problem,some people don't even know they have them and uses the same amount of power as a kettle)If in doubt she should get in contact with her energy provider who are legally bound to check the meter.By the way every time the meter gets read the meter reader has to check the tamper seals etc,.