The risk of legal action shouldn't change one's conduct.
So yes, you should always try to do the ethical thing. But your moral calculation should at least consider the risk of being sued and take that properly into account.
At a big hospital, the doctor might not have to pay for lawyers personally, but the hospital or the insurance company might have very clearly defined rules for when the lawyers get paid for, so the doctors may not have much choice about treatment.
>the doctors may not have much choice about treatment
What do you mean by this?
I think it's reasonable to assume insurance companies will defend a doctor whose conduct is based on solid evidence or law. Are their rules not aligned with current medical practice?
"Did you do this?" "Yes." "Why didn't you do this instead?" "Based on the circumstances, it didn't sound reasonable" "So you're not experienced enough to consider that as an option? Should you be practicing medicine?" etc.
Once you get convicted, that sticks with you like a stigma, even if it's total B.S.
This forces doctors/hospitals/etc. to follow exact established procedures to try and reduce the possibility of getting sued. It's called defensive medicine. Their decisions are what are best for them, and not necessarily in your best interests, and let me say this: I don't blame them for it. Having grown up with doctors, lawyers, and lawyers who defend doctors in my family, I can tell you getting sued positively sucks . . . . except for the plaintiff's legal team, they pretty much win, if they are any good at it.
From 2000 to 2004, in one of my country's states, 372 doctors were taken to court but only 23.9% were condemned¹. The number of lawsuits have been increasing ever since; I found a news article with more recent figures from another state but couldn't find the actual source of the numbers. It said 35% of verdicts were guilty.