First, the system described by OP is super easy to see who is gaming it. Everyone knows, too! So it doesn't even fail your first test of "the system can't tell

First, the system described by OP is super easy to see who is gaming it. Everyone knows, too! So it doesn't even fail your first test of "the system can't tell". The system can tell. It's just not doing anything about it. That's the failure i'm describing. Beyond that: If people work around the system, it will never work, regardless of the system. Any system can be worked around, good or not. There are no magically good systems that can't be worked around, or don't even incentivize people to work around them. All good systems try to deal with bad actors in some way. If they don't, they fail. Plain and simple. Saying that any system that doesn't work because it has bad actors is a bad system is silly. You will no-true-scotsman your way into having no systems at all.