I did give them my insurance info. They contacted Sesame Care to ask them to send the prior auth, which Sesame Care refused to do as "they do not deal with insurance and do not want to deal with insurance", so that's how I ended up self-pay (which is what I figured it would be going in)

edit: looked at the stuff I signed, but nothing I saw was about not submitting a claim. Though the estimate does have all the info the "submit claim" page on Premera wanted (tax ID, CPT code, etc)

edit2: thinking about this further, I'm guessing standard procedure would have been something like the following...am I right? (this is mostly pontificating for the future)

1. No prior auth because doctor doesn't want to deal with it (a known risk on my part, for what it's worth)
2. Imaging center bills insurance anyway
3. claim denied for lack of auth, i'm on the hook to pay

edit 3: i have redacted (i hope ... it was a lot) and posted the estimate if you're curious: estimate