Most of the time here in Detroit, unless it has been specifically requested, and/or in the case of Catholics (that I know of), the caskets are open during the funeral; usually being closed just prior to the eulogy beginning. At that time, there is usually a very emotional closing of the casket where the immediate family members are allowed to go to the casket, together, and watch the casket being closed. Sometimes, a specific family member may even be the one who lowers the casket on their loved one.
I have even seen caskets REOPENED for perhaps out of town family members who arrive a bit late, after the casket has been closed.