The "Green Line" is the pre-1967 border of the State of Israel, and "crossing it" means going into the ancient Jewish regions of Judea and Samaria, AKA the West Bank.
And apparently is does make one's bowel movement more odorous, this according to the Sept. 30, 2013 PNN ( Palestine News Network) Headline : Israel Uses Settler Feces as Bio-Warfare.
Here is a quote from the article:
The Israeli army has developed a large vehicle for spraying sewage waste and feces at Palestinian protestors and homes, reportedly, in the towns of Abu Dis, Aizariah, Bil’in and Nabi Saleh.
Spraying sewage waste has become so common a weapon used by the Israeli Army that the combination of sewage water, feces, and human urine has been named “skunk”. B'Tselem reports that ‘skunk’ and the vehicle used to disperse it, have been added to Israel's armory for crowd control.
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Here's a short youtube about the skunk mixture.