The scola does it at the seminary. A good question would be to ask anyone who has spent much time at the Winona seminary if the scope ever did this. I assumed it is something only done by clergy, if present, but considering the Virginia seminary chapel layout, there isn't room for a scola, so they form a circle in the middle, which allows the rest of the clergy to see the scola director.
From a pastoral perspective, it was certainly incuмbent on the priest in charge to explain to the congregation the change in the schola's positioning so as to reduce scandal, if the schola does not normally stand in the center.
However, the positioning of the schola cantorum in the center of the choir is actually traditional. And the position of the choir immediately before the presbyterium/chancel (the area immediately surrounding the altar where the principal liturgical action occurs) is assumed by the rubrics and all modern legislation until just shortly after Vatican II. The matter is actually theological and rubrical, not acoustical. But this traditional position would strike most readers here as odd for several reasons:
1) for those who are American, most American Catholic churches were not built in the fashion of the collegiate/cathedral/monastic churches of Europe; its liturgy and Office were often said privately or with the most minimal ceremonial, and thus there was no need for a traditional choir space before the presbyterium. But for those in Europe, the sight of a choir area before the presbyterium is normal.
The idea that parochial churches should not principally model these older European exemplars, despite the differences in liturgical needs, is one of the dangerous and false prejudices of the modern Liturgical Movement that had disastrous effects later on.
2) another difference between modern American (i.e. less than 300 years old) and traditional European Catholic churches was the complete absence of a choir screen and/or a rood screen. Of course, these were mostly removed even in the European churches, but a secondary visual element usually accompanied their presence: the choir would be elevated by at least one step above the nave, and the presbyterium would be elevated by at least one more step above the choir. Often many steps were involved, creating a striking visual distinction that represented the hierarchy ascending from laity to clergy, from earth to heaven, as one approached the altar. The choir and rood screens further emphasized the mysterious dignity of the liturgy by obscuring the vision the further out one stood in the church.
These former architectural aspects would have helped hide the fact that the schola was standing in the center of the choir, but in a modern church, they are now visible for all to see and thus often may be distracting for those unaccustomed to the practice.
3) if one observes most European choirs, one will often see the old stands that held the large illuminated choirbooks on them. It was from these large books that the schola cantorum would stand around to chant the more elaborate propers (one can see this practice in old illustrations of monks standing around a large choirbook and singing, often deliberately depicted with humorous expressions, as one still sees singers unconsciously make today). In more prestigious churches, one would find multiple stands each with its own choirbook, allowing the schola to remain in the choir stalls and a single elevated platform set in the center of the choir for the schola director to conduct (sometimes the choir organ console was placed near this stand as well; otherwise it was to the side of the choir stalls, e.g. Notre Dame). In modern times and churches, even though we no longer use these large choir books (thanks to the cheapness and readiness of modern printing allowing each singer to have a portable Liber), the formation that followed from the older practice still held over. Its only benefit nowadays is ease of following the schola director by standing in close proximity to him.
The idea that the laity should be able to see the liturgical action unobstructed at all times is a totally novel idea that originated with the corrupted influences of the Liturgical Movement, which followed Enlightenment rationalist principles in insisting that the laity should understand the entire liturgical action and that all vertical and obscuring elements should be removed and leveled. We see the Society has unfortunately followed this principle in its new Immaculata altar that will not feature a traditional baldacchino, nor a traditional choir space.