Do I absolutely need to fill out a coordination of benefits form if I have two different health insurance plans?

Hi Folks,

Somewhat random question I’m hoping someone can help me answer. A bit of context: I live in California. I have Kaiser Permanente HMO through my wife’s work (kaiser is a health system that has its own facilities and its own insurance and they only work together) and will have a Blue Shield PPO through my own work starting January 1. Kaiser insurance isn’t accepted anywhere that isn’t inside Kaiser’s provider network (except for, like, ER visits and urgent care) and Kaiser facilities don’t accept outside insurance. So, basically, Kaiser is totally separate from non-kaiser insurance and doctors.

I like Kaiser for some things and don’t like it for others (basically, if it is routine, Kaiser is great; if it requires some imagination and isn’t as routine, Kaiser is pretty dismal.) This is why I’m adding my own work’s insurance this coming year since I’ve got a few health issues that Kaiser has been pretty sub-par about and I’d like the flexibility of just going to whatever specialist I’d like without having to deal with Kaiser’s bureaucracy and firewalls.

My question (finally) is: does anybody know how coordination of care works in this bizarre scenario? Would it be possible for / what would be the potential pitfalls of me to just not disclose to Kaiser that I have other insurance and not disclose to my other insurance that I have Kaiser and just use one when I feel like it and the other when I feel like it?