Are the cavities next to a permanent tooth?
How good are you really at reading radiography?

I don't know what he is doing with regional anesthesia and buffering medication.

And recommending a crown even though there isn't a cavity or it isn't painful doesn't mean it isn't the best thing for your tooth. Teeth start to fracture and we can see those. If it's getting rough to where you are feeling the fracture or wear on your tooth, you may very well need a crown to prevent the tooth from breaking.

You can wait until it breaks or hurts, but then you may also be paying for a root canal.

Also, decay is a infection. If the teeth will come out soon, there is no harm and leaving the cavities, which may be the case with your 10 year old. But baby teeth that will be in there for over a year can cause other teeth- permanent teeth- to get cavities. Baby teeth also get infected faster because the decay doesn't have to be as deep to get into the nerve. So don't think that just because baby teeth are going to eventually fall out that the cavities don't need to be treated.

I see so many people with the attitude that dentists are trying to take advantage of them if they are telling them things need to be done and there is no pain.

Well guess what? These are the patients that are missing a bunch of teeth because they wait until the tooth is so bad that it either costs too much to fix it or it isn't salvageable. In the end, it's your mouth and you have to live with it everyday.