I post about half my sales as large letters. In 9 years I've had 3 (I think; less than 5 anyway) INR claims. That's on over 4000 sales. About 2000 letters.

I suppose it depends on your market, but mine seems to be honest. Either that or there are less online shoplifters around than these boards would indicate. Given that people generally only come here when they have a problem, I suspect option b.