Good point but I believe the issues are dissimilar. With downloading you are dealing with 100s of millions of people who can trivially foil all efforts to stick

Good point but I believe the issues are dissimilar. With downloading you are dealing with 100s of millions of people who can trivially foil all efforts to stick them with a bill with a few clicks. Return fraud is orders of magnitudes smaller and as it involves physical goods changing hands spoiling anonymity. A single user committing a single act of fraud might yet retain relatively good odds but a massive portion of fraud as with retail theft is perpetrated by a minority of offenders which could well be correlated by requiring an ID for all returns and dealing with a tiny number of major offenders very harshly. An environment in which you hear news about fraudsters facing prosecution or financial ruin would be perceived as riskier further dissuading offenders.