I am from the South Texas hinterland, just across the Rio Grande from Mexico. The Cathedral has the Mariachis on from time to time. The music is just not fitting, in my opinion, for the Holy Sacrifice of the Mass. When the first rector of the Cathedral took over, the first thing he did was get rid of the Mariachis and restore the use of the organ. The Masses were beautiful and sacred. When the administrator took over, he brought back the Mariachis, much to my chagrin (I was assisting with liturgy and worship at the time). The music became quite dreadful and all sense of the sacred was gone. I tried my best to express that to both the administrator and the local ordinary, but, to no avail. When the next administrator came along (a native of Mexico), he got rid of them and restored the organ. Unfortunately, they’ve come back.
The Mariachis seem to have no sense of liturgical seasons, let alone liturgical propriety. For example, during the season of Lent, when the music is supposed to be subdued, they were there with trumpets blaring away. During the first Sunday of Advent, they launched into the Gloria. People do come because they like to listen to them, but, in my opinion, the Mariachis add nothing to the Mass. The sad fact is that they detract from the sacred, solemn and dignified nature of the Holy Sacrifice.
Mariachis are more common to festivals, restaurants and greeting convention groups. In fact, the when a convention or a tour group visits our city, they are sometimes entertained by a Mariachi band. The style is completely secular and are a very recent innovation. The Matachines, on the other hand, date back some 500 years, to the time of the Guadalupe apparitions.