Egypt learned on other's mistakes for once. They saw how Jordan welcomed Palestinians on their land and they repaid the kindness by launching a coup against the government in 1970. No wonder not a single anti-Israeli coalition country is willing to deal with Palestinians directly at their own home and are keeping borders watertight :) .
Don't forget that after being expelled from Jordan, Arafat relocated to Lebanon where he proceeded to take over the South ("Fatahland"), start a civil war, and pull in Israel with constant attacks across the border. Until Israel kicked them out in 1982, the Palestinians played the disruptive, parasitic role in Lebanon that Hezbollah plays today. In fact, Hezbollah rose to power precisely by filling the void left by the Palestinians in 82.