If you want there to be no chance of client-side fraud, use TurboFloat in your app and host the TFS on your infrastructure.
If you want there to be reduced (but non-zero) chance of client-side fraud, use the latest TurboActivate.
Regarding date/time shenanigans and "testing", we don't support cooked-up experiments. We do reduce client-side fraud in real-world usage. Not faked experiments that don't match reality. We've been over this multiple times with you.