Newsagents have told me about a crackdown by magazine distributor Gordon and Gotch on magazine returns claims. They are cross-checking supply and sales data against returns claims and going back to newsagents where the data does not add up.
While Gotch has spot checked returns for years, they now appear more attentive. Newsagents over claiming returns are more likely to be caught.
While there is plenty wrong with the magazine distribution model, consistent over-claiming of returns is not justified and could result in criminal proceedings if Gotch decided to take it that far.
My advice to newsagents is to have a structured transparent process for scanning returns as well as for arriving and selling stock. Fudging figures to get a bigger credit that is not justified in supply and sales data will result in you being caught.