None of the four made a sound, an agreement they had established beforehand—here, they were to kill, not to converse.
Isaias Vasquez had previously informed everyone that he would be waiting for Carson Flores at the ancestral home, which was common knowledge among the major families in Xijing. Carson Flores would bet that among these surrounding woods, there might be scouts from other families or Sects hidden, or surveillance equipment silently installed, with cameras aimed straight at the Vasquez family's old residence.
Their actions now were likely being watched by many families, so it was better to keep their identities hidden if possible.
Even if Isaias Vasquez recognized them, as long as they didn't reveal themselves, they could deny everything.
Unless someone could overwhelm and forcefully overpower them, there was still a need to present credentials to justify their actions.