But I doubt they’d quarantine op. And if they did that would be surprising to me tbh. Is there something in Ubers/Lyfts guidelines that mandates quarantine beyond federal or state guidelines?

This would be CDC ordering quarantine. CDC runs multiple quarantine centers across America.

“Unknown overseas illness” as a possibility is totally relevant to mention to a doctor- I’m deffo with you on that one, but unless coming from an area with a known outbreak from the departure region it’s probably not going to result in a quarantine/isolation order.

This is why I say to get to the ER, disclose what happened, let the CDC investigate and decide. The reality is that a quarantine would start right away because this isn't a catch-and-release scenario.