I wrote the first version of this at Shopify.

We anticipated the need to see this kind of behaviour, so there's clear auditing trails for everything that HR and Accounting can see where the bonus money's going.

Having said that, we haven't seen this problem appear yet.

Yup - this system gamifies reciprocal altruism, creates cliques and circular thank-you unicorns, and generally sounds de-motivating by quantifying the exact dollar value of a thank you.

I have seen this happen on Yammer. Now tie bonus to that and you have got a worse system than traditional performance reviews.

Yeah, we had a little "thanks" program at work that had similar issues. People tended to just reciprocate praise, because it didn't cause any drama, and both people made out.

simple - fireable offence