The court's agents found people careful about great gift but careless about tithes, so they ruled not to rely on Am Haaretz.
Question 2
What is separated from Demai?
From Demai, one separates gift of tithes (with death penalty) and second tithe (no loss as owners eat it), but not first tithe or poor tithe.
Question 3
What does a guest do unsure?
Since on Shabbat it's forbidden to separate gifts and tithes, he makes a condition on Friday and specifies verbally the parts to separate, and on Shabbat he whispers and eats.
Question 4
Why is a baker exempt from tithing?
The sages exempted the baker from second tithe since authorities monitored his prices and he couldn't raise them, thus only imposing gift of tithes and second tithe. The buyer must separate second tithe.
Question 5
When two people harvest grapes together?
Since the fruits mixed before distribution, there is no valid separation, and one cannot claim his previous separation applies to his share. Therefore, he separates like Demai on half of what he takes — the part of the Am Haaretz.