It could be interesting for corporate cards used to pay expenses, I wonder what would happen: would everyone start spending less, trying to avoid shame, or would everyone actually start spending more, trying to match the highest spender (because they will then see higher expenses are acceptable, and feel cheated if they didn’t make use of that – naturally, the highest spender will start to spend more to assure his superiority etc. etc.)

It’d be sweet to combine this with other info, such as GPS tracking: “Hey, I saw you went to the store but didn’t buy anything… WTF?”