A quick internet search will give you articles from newspapers across the country that give examples of communities in their area that are recommending trick-or-treating on Saturday, other communities recommending Sunday, and others not recommending either day.
It’s not a Utah question. It’s something being asked all over the country.
So, if you have kids, pick a day or go both days. If there are kids in your area, have treats available both days. It’s not a big deal, and certainly is no reason to be critical of someone who is doing something differently than you.