A new contribution on this issue is from Pope Benedict XVI in 2007 Apostolic Exhortation Sacramentum Caritatis. Encouraging those who cannot receive communion to join the communion procession is not helpful. It is likely to cause confusion. Someone who correctly thinks they should not receive Communion may decide they should, since another person who should not is in the Communion Procession.
Pope Benedict wrote:
“50. … In this regard, I would like to call attention to a pastoral problem frequently encountered nowadays. I am referring to the fact that on certain occasions – for example, wedding Masses, funerals and the like – in addition to practising Catholics there may be others present who have long since ceased to attend Mass or are living in a situation which does not permit them to receive the sacraments. At other times members of other Christian confessions and even other religions may be present. Similar situations can occur in churches that are frequently visited, especially in tourist areas. In these cases, there is a need to find a brief and clear way to remind those present of the meaning of sacramental communion and the conditions required for its reception. Wherever circumstances make it impossible to ensure that the meaning of the Eucharist is duly appreciated, the appropriateness of replacing the celebration of the Mass with a celebration of the word of God should be considered. (footnote 153: Cf. Propositio 35.)”
The full document is at
vatican.va/holy_father/benedict_xvi/apost_exhortations/documents/hf_ben-xvi_exh_20070222_sacramentum-caritatis_en.html .
Here are some quotes from the liturgical book “Rite of Christian Initiation of Adults” which I think highlight how wrong it is for the blessing to be given during the Communion Procession. Ideally catechumens should not be at the Liturgy of the Eucharist, never mind in the Communion Procession:
In describing the Rite of Acceptance:
“44. … The rite consists in the reception of the candidates, the celebration of the word of God, and the dismissal of the candidates; celebration of the eucharist may follow.” Although it has for this ceremony: “67. If the eucharist is to be celebrated, the catechumens are normally dismissed at this point by use of option A or B; if the catechumens are to stay for the celebration of the eucharist, option C is used; if the eucharist is not to be celebrated, the entire assembly is dismissed by the use of option D.”
“75. … 3. The Church, like a mother, helps the catechumens on their journey by means of suitable liturgical rites, which purify the catechumens little by little and strengthen them with God’s blessing. Celebrations of the word of God are arranged for their benefit, and at Mass they may also take part with the faithful in the liturgy of the word, thus better preparing themselves for their eventual participation in the liturgy of the eucharist. Ordinarily, however, when they are present in the assembly of the faithful they should be kindly dismissed before the liturgy of the eucharist begins (unless their dismissal would present practical or pastoral problems). For they must await their baptism, which will join them to God’s priestly people and empower them to participate in Christ’s new worship.”
“83. … 2. Gradually the catechumens should be admitted to the first part of the celebration of the Sunday Mass. After the liturgy of the word they should, if possible, be dismissed, but an intention for them is included in the general intercessions.”
(The Rites Volume One, Liturgical Press, 1990, ISBN: 0-8146-6015-0. Also at RCIA introductions for England and Wales:
catholic-ew.org.uk/liturgy/Resources/Rites/RiteRitual.html#RCIA .)