Tamas, the tunnels are not the main way into Gaza, there are of course border crossings with Egypt and Israel as well as access to the sea. I don't know if the tunnels are used to bring food, but I don't see why they should except at times when Gaza is being blockaded. Of course, Egypt is no longer blockading Gaza. Anyway the question about the peace treaty is a difficult one. The current Egyptian government is led by the Muslim Brotherhood, who cooperate with Hamas, so I don't see why they would want to militarize the Sinai?