This is about all you can do. But you're right. You have to explain it and document it: "It's trivial to change User-Agent, and any decent hacker would probably

This is about all you can do. But you're right. You have to explain it and document it: "It's trivial to change User-Agent, and any decent hacker would probably not be using 'curl' as their User-Agent. We can look at logs from past events to validate this assumption."