Rashi explains that the Chaver feels responsible for the Am Ha’aretz due to ‘Lifnei Iver’ (putting a stumbling block before a blind man); why shouldn’t he simply assume that fresh fruit off a tree is certainly Tevel (as an Am Ha’retz, he surely wouldn’t ponder that the Chaver feels especially responsible toward an unrelaible Am Haa’aretz)?
When placing the Eruv on a tree (below ten tefachim) why can’t he rely on instructing a goy to remove it for him – something which is permitted for the sake of Mitzvah – rather than removing it himself Bein Hashmashos (which is only permitted according to Rebbi)?