the idea that anyone can just show up in heaven, if one believes in heaven, is pretty preposterous....
you have people that live as Christians, trying always to do good, and you have people that always are engaged in sin....
you have people that think bowing their heads and saying "Jesus" a dozen times in a sentence somehow makes them pious, reguardless of what havoc they bestow on their fellow man....
now, how can we believe that God accepts everyone no matter what...the Bill Clinton's with Mother Theresa....without a hint of discrimination....
why would humans ever pray, ever do what's right without the knowledge that our actions and our prayers actually MEAN something .....
thus, we have "heaven" and we have "hell" and we have places in between....purgatory or limbo, as we Catholics believe....
I have to tell you, that going to a very conservative nun's school, the little ones who never got baptized were always thought of as heaven bound, just like people that never learned the Word of God were heaven bound for the most part....
we were always taught that our God was a wonderful, loving Father......
Just to clariry, purgatory is a temporary state of purgation. The souls in purgatory will eventually reach heaven.
The limbo of the infants, OTOH, is a very complex subject.