A learned scholar like the Bhaṭṭācārya can detect such imposters, and when he finds them out he at once rejects them.
In the case of Lord Caitanya Mahāprabhu, the Bhaṭṭācārya tested all the symptoms in the light of the śāstras. He tested as a scientist, not as a foolish sentimentalist. He observed the movement of the stomach, the beating of the heart and the breathing of the nostrils. He also felt the pulse of the Lord and saw that all His bodily activities were in complete suspension. When he put a small cotton swab before the nostrils, he found that there was a slight breathing as the fine fibers of cotton moved slightly. Thus he came to know that the Lord's unconscious trance was genuine, and he began to treat Him in the prescribed fashion. But Lord Caitanya Mahāprabhu could only be treated in a special way. He would respond only to the resounding of the holy names of the Lord by His devotees. This special treatment was unknown to Sārvabhauma Bhaṭṭācārya because the Lord was still unknown to him.