Ghosn is a Lebanese citizen (among French and Brazilian) and he chose to flee to Lebanon. In many countries, such as the US, you don't need a passport to return home. You don't need any documentation, in fact. The border agency will detain you and question you for days until you can sufficiently prove your citizenship, but they are legally obligated to let you back into the country. I don't know whether this is the case for Lebanon or not.

Commercial flights check your passport before you board, because there are regulations and they like to cover their own ass, but private charter flight don't have these checks if you pay enough.