They would observe first. Even if they wanted to accept disciples, they would wait to see if the person attained any accomplishments. Not every Dharma Idol that carried the power of the natural laws would be extraordinary, and not every Dharma Idol that seemed mediocre at first was deemed to stay that way. An example would be Molton. When he first entered the Holy Land, his potential wasn't outstanding, and he wasn't valued. Thereafter, he suddenly broke through the Initial and Middle Phase Heroic Soul Stages in two consecutive years, breaking a cultivation record in the Holy Land. His Dharma Idol had undergone a qualitative transformation for the third time, a rare occurrence. It was what led the 7-star Great Teacher Cleo to make an exception and accept him as a disciple.
Therefore, for a high-rank Great Teacher to accept you as a disciple while you were still a newcomer, you would need a great deal of talent, something that didn't come by easily.