Has anybody had success doing this? Start nice and request that your account no longer receive UberPool. State that you will NEVER accept an UberPool request. You no longer want to temporarily disabled or logged-off after refusing 3 requests. Be honest, the records may be checked.
Give a valid reason, fear for your safety because of UberPool increased risk compared to X. Unrelated riders may argue with each other. You do not want to referee or risk being drawn into their argument. Your increased risk is not worth the small payment, compared to X.
Actually, UberPool payment to drivers is not worth it even without the increased risk.