Describe the perplexing interaction between Sai and the two Goan visitors, focusing on the reaction of the onlookers.

The narrative in Chapter 36 details an event where two men from Goa visited Sai. A puzzling situation arose when Sai asked one for fifteen rupees as Dakshina but rejected an offering of thirty-five rupees from the other. The text explicitly states that "Everyone was greatly surprised by this." This unequal treatment was so noticeable that it prompted a specific reaction from Madhavrao, also known as Shama, who was also present. Seeing what he perceived as partiality, Shama decided to question Sai Baba directly to understand the reason behind his actions.