OK, so now your crosses and images are veiled, right? And you've left off singing all Gloria Patris, and have entered the depths of Passiontide. The Propers in The Lutheran Hymnal are wrong at this point; Lutheran Worship partly corrected the error, leaving off the Glorias for Palm Sunday, but condensing Passiontide to one week only, the same as Holy Week. I don't know offhand what Lutheran Service Book did, because they erred in omitting the Propers from the hymnal altogether.
Anyhow, here's where these customs arise, in case you were wondering.
The "hiding" of Jesus, by veiling statuary, crosses, and images, is because of the last part of the Judica Gospel (St. John 8) in which we are told that when the Jews took up stones to cast at Him, "he hid himself," and passed by. So the hiding of Jesus' image is a vivid reminder of what happens when He is not taken seriously: He withdraws. An added reason for penitence thus arises here.
The "hiding" of images of saints is due to the thought that it would be unseemly for a saint not to be hidden if the Master Himself is hidden.
The omission of the Glorias is a further indication of a liturgical descent at this time.
In addition, it is actually not traditional to observe any occasional feasts of any kind during Passiontide. Therefore the new calendars are also wrong, which transfer Annunciation to the day after the 25th. No, it goes the day after the Easter Octave, which this year is Monday, April 16th.