QMessageBox and QApplication::quitOnLastWindowClosed

It would be nice if QMessageBox widgets have the attribute
Qt::WA_QuitOnClose set to false by default.

Consider the following use case:
An application may start by showing a message box with some text for example:
"You have an evaluation license that will expire in 30 days."

Then when the user presses OK, the main window should be shown.

Instead the application will terminate when the message box is closed.
and the main window is never shown unless QApplication::quitOnLastWindowClosed is set to false.