…Our advent wreath in the church was decked out in these horrid looking royal blue candles!!!
In the United States of America this means there has been a failure to comply with a liturgical book.
The Book of Blessings has a blessing for the Advent Wreath, which is for the USA only. It is not in the Latin edition of this book.
The Introduction to the blessing has:
“1510 Customarily the Advent Wreath is constructed of a circle of evergreen branches into which are inserted four candles. According to tradition, three of the candles are violet and the fourth is rose. However, four violet or white candles may also be used.”
(From Book of Blessings, Liturgical Press, Minnesota, 1989, ISBN 0-8146-1875-8, page 573.)
So four blue candles is a failure to faithfully follow a liturgical book, in the USA. Therefore it is an offence under the Code of Canon Law:
“Can. 846 §1 The liturgical books, approved by the competent authority, are to be faithfully followed in the celebration of the sacraments.”
(The Code of Canon Law: New Revised English Translation, HarperCollins Liturgical, 1997, ISBN 0-00-599375-X, page 197).
I think a liturgical book should be followed, whether it is for a sacrament or not. But I suppose a stronger case could be made if were displayed and/or lighted during the Eucharist.