So far as reception of the sacrament is concerned, I agree with Jürgen Moltmann: Jesus' invitation to his Table is prevenient – there for the taking. For me the Eucharist is multivalent and its meanings inexhaustible. But the question as to age or condition (or whatever) at reception of the sacrament interests me especially since the Reformers insisted on keeping Word and Sacrament tightly yoked; in losing the Word, the late Medieval Church had lost the essence of the sacraments, and I’m convinced there have been and continue to be churches that have "lost" the sacraments and in doing so have lost the Word's essence, since God’s self giving in Jesus Christ is at the heart of both proclaimed Word and visible Word.
But part of the reasoning against admitting infants and young children to the Table is in the need to retain the unity of Word and Sacrament, so for some people the question becomes whether the potential recipient has heard and received the read and proclaimed Word. This evening I've simply putting the suggestion out for consideration since, despite having said that, I feel none of us is "keeper of the sacraments" and authorized to exclude those whom Jesus already has included.
One more note, though. Robert McAfee Brown suggests persons who in their daily lives haven't been practicing justice, righteousness, hospitality and inclusion maybe should be excluded from the eschatological Eucharistic feast! Any ideas on that?