Question:
Answer:
The general rule of thumb to remember is: “no other person, even if he be a priest, may add, remove, or change anything in the liturgy on his own authority” (Sacrosanctum Concilium, 22.3).
In addition, General Instruction of the Roman Missal references the orans posture with the phrase “with hands extended.” It is instructed to be done twenty-eight times and is used as a direction only for the priest(s)—the laity are never directed to pray “with hands extended.” Given that it is clearly a directive in the GIRM, to add it to any other part of the liturgy would be a violation of the above stated liturgical rule.
More to the point, the Church excludes the laity from praying in this manner in the 1997 instruction Ecclesiae de Mysterio [EM], which a number of congregations and pontifical councils of the Holy See co-authored, including the Congregation for the Doctrine of the Faith:
To promote the proper identity (of various roles) in this area, those abuses which are contrary to the provisions of canon 907 [of the Code of Canon Law] are to be eradicated. In eucharistic celebrations deacons and non-ordained members of the faithful may not pronounce prayers — e.g. especially the eucharistic prayer, with its concluding doxology — or any other parts of the liturgy reserved to the celebrant priest. Neither may deacons or non-ordained members of the faithful use gestures or actions which are proper to the same priest celebrant. It is a grave abuse for any member of the non-ordained faithful to “quasi preside” at the Mass while leaving only that minimal participation to the priest which is necessary to secure validity. (EM, Practical Provisions, Article 6, §2, emphasis added)
The instruction’s longer official title is On Certain Questions Regarding the Collaboration of the Non-ordained Faithful in the Sacred Ministry of the Priest, which was promulgated on August 15, 1997. The Church issued the instruction to address a number of unauthorized modifications taking in the liturgy.
As to the reason why this matter is rarely addressed, that most likely has to do with pastoral sensitivity. If a handful of people are innocently praying in the orans position, the priest is not going to go out of his way—during the recitation of the Lord’s Prayer—to embarrass them or cause them to feel uncomfortable. Their action, while not liturgically correct, is best addressed otherwise.
In that light, a priest offering the Mass could address the matter earlier in the liturgy, e.g., at the beginning or end of his homily, and then perhaps give a brief reminder right before the praying of the Lord’s Prayer.