It's my understanding that an infant baptized as a Roman Catholic would have a punched ticket into heaven by virtue of being baptized into the Roman fold.
This is too funny because when I first said this I thought it was the most innocent of comments. :) I was thinking along the lines that because there is no assurance in Catholicism, the ticket is never punched into heaven. Never during life. Therefore, Catholics spend their entire lives sitting on the train, even with a ticket (stub), but it is never legitimated by the conductor coming through and punching it, thus, verifying it. The punching cancels out the ticket and stub in order to prevent fraud. My little analogy was that Catholics can never be sure that they will not become a fraud in God's eyes, and lost forever. Therefore, their tickets are never punched.
Your premise is incorrect. The assurance of salvation exists following baptism, and/or following sacramental absolution of sin, till a mortal sin is comitted.
If you wish to caricature this as ping-pong assurance, you may. I would, however, add that for a good Catholic avoidance of mortal sin is quite achievable, because he draws on the grace of God weekly at Mass and is strengthened by the Eucharist. While many suffer through recurring setbacks, just as many have a successful life journey on their way to sanctification.
I recall discussing this before.