[mirimir]

Soaking in a hot spring seems unnecessarily risky. There's too much chance of substantial temperature change. Better to soak in a pool that's fed from a hot spring. Rather than mess with park police, find hot springs where it's allowed.

[dboreham]

Locals know places where it is relatively safe to soak in the hot water. Heck, you can go to Chico and pay a few bucks there to soak in the same water at no risk and drink a beer..