Friends dont let friends stay in bad relationships! Or do they? I'm the type of person that feels like it's best to be completely honest when asked an opinion on something.
What to wear?
What's healthier to eat?
Should we go out tonight or stay in?
But a tougher question is....
Do you think I should stay with my boyfriend?
Well, if she does then your opinion looks pretty ill if it's a negative one. Then she looks at you differently. Or both persons think you're trying to break them up for your own selfish motive or some other bullshit when in the end all you wanted what was best for your friend.
In some cases you may realize that their own delusions mean that they could never have actually been your friend. In other cases they'll realize why they got the restraining order and start to make their own positive changes in their life (hopefully with your help). Either way, lessons will be learned by all and its what you do with those lessons after the fact that truly matter.