Matthew 18:10 "Children's angels always behold the face of the Father" - what does this mean? Matthew 18:10 seems to put forth an idea that children have a certain privilege over adults:


  Take heed that ye despise not one of these little ones; for I
  say unto you, That in heaven their angels do always behold the face of
  my Father which is in heaven (Matthew 18:10)


Since any child, if it doesn't die in early age, grows up and sooner or later becomes an adult, one can suggest that children are losing that privilege as they grow up. 

How has this verse been traditionally interpreted in Catholicism, Orthodoxy and Early Protestantism? What is an overview of the major views in mainstream Christianity in this regard?
For Catholics, one can read from the Catechism paragraphs 328-336.  In terms of a guardian angel, we read the following, showing the Catholic Church believes children do not lose their angels:

336 From infancy to death human life is surrounded by their watchful care and intercession. [Cf. Mt 18:10; Lk 16:22; Pss 34:7; 91:10-13; Job 33:23-24; Zech 1:12; Tob 12:12.] “Beside each believer stands an angel as protector and shepherd leading him to life.” [St. Basil, Adv. Eunomium III, I: PG 29, 656B.] Already here on earth the Christian life shares by faith in the blessed company of angels and men united in God.

St. Paul makes an interesting reference to his Guardian Angel here:

Acts 27:23 For last night an angel of the God to whom (I) belong and whom I serve stood by me 24 and said…

Further, this makes it sounds as if John's Guardian Angel was involved:

Rev 1:1b He made it known by sending his angel to his servant John

Also the following:

Heb 1:14 Are they not all ministering spirits sent to serve, for the sake of those who are to inherit salvation?
Ps 91:11 For he commands his angels with regard to you, (Heb 1:14) to guard you wherever you go. (Ps 121:3; Prv 3:23) – Referenced by Satan in Lk 4:10–11/Mt 4:6 when he tempts Jesus in the desert
Mt 18:10 (Ez 34:1–3 &amp; 16; Lk 15:3–7) “See that you do not despise one of these little ones25, for I say to you that their angels in heaven always look upon the face of my heavenly Father.”