What is the function of the lug seat inserts on the recalled Honda Civic aluminum wheels?

They are hard steel inserts that ensure a strong, secure fit for the lug nuts on the softer aluminum wheel.

What could happen to the aluminum wheel if the lug seat inserts are missing when lug nuts are installed?

The area where the lug nut installs could become deformed, causing the nuts to work loose.

What could happen to the aluminum wheel if the lug seat inserts are missing when lug nuts are installed?

The supplier's factory was in Italy.