My oldest daughter (6) gets nosebleeds, but the other two have had no symptoms.
My husband's sister died of a ruptured cerebral AVM in 2002. I did my own research on AVM and concluded that the family must have HHT (lots of nosebleeds). My husband had the genetic test and it confirmed an ALK-1 mutation. His dad, two sisters and one brother all got tested and all have it. Another sister has it clinically and one brother hasn't been tested yet.
We live in the United States and I think that makes everything easier. There is a huge fear of being sued among doctors so they are usually willing to do lots of tests on patients to make sure nothing gets missed. I don't know if that is a good thing or not, but it drives a lot of medical decisions here.
I also disagree that cerebral AVMs are not treatable. Even if it was in a location that couldn't be treated, I would want to know if my daughter had one. I would alert the school/daycare, have her wear a medical bracelet, etc.
Aimee