https://tamebay.com/2019/08/royal-mail- ... abels.html
Royal Mail Revenue Protection are the people who try to stamp out postage label fraud. There are two main types we’ve seen used by sellers over the years – printing a label twice and sticking it on two different packages and printing a label, cancelling it and then using it anyway.
There are other types of fraud of course, such as under-declaring the weight of individual items or mail bags and fudging the number of items sent via PPI, but it’s the label printing that Royal Mail appear to have taken recent steps to address.
Printing a label twice for two different packages has been somewhat eliminated by the use of Royal Mail 2D barcodes. Royal Mail will be all too aware if the same label is in their network twice and this will quickly become apparent then they scan the label at the point of delivery.
Cancelled labels are more tricky to catch, but if you cancel a label today you’ll get a message warning you that the information will be automatically shared with Royal Mail Revenue Protection. If the label be used and identified within the Royal Mail Network, you’ll be charged for it on your account plus get hit with an additional handling fee (which will probably be around a tenner – more than you probably would have paid for the label in the first place).
“Please be aware labels generated on orders which are then reset are no longer valid and must be destroyed. If you wish to despatch this order, please generate a new label and attach it to your item.
Cancelled label information is automatically shared with Royal Mail Revenue Protection, and should a cancelled label be identified on an item in the Royal Mail Network, you will be charged on your account and an additional handling fee applied.”
– Royal Mail Cancelled Label Flow
One might speculate that there are some sellers who cancel a proportion of labels and use them on a regular basis. One might even think that this is a commonplace practice for some groups of sellers. Be warned however, if Royal Mail Revenue Protection start adding hundreds of handling fees to your account it will have been a lot cheaper just to pay for your postage like everyone else.