How to defend against users with Multiple Accounts?

Question

We have a service where we literally give away free money.

Naturally said service is ripe for abuse. To defend against this we do the following:

• log

Answer 1

Sometimes the only way to prevent people abusing a system is to not have the system in the first place.

If you're doing what you say you're doing, "giving away money to people", then surprise surprise, there will be tons of people with more time available to try to find ways to game the system than you will have to fix it.