ضَوَابِطُ انْتِفَاءِ الضَّمَانِ فِي حَوَادِثِ السَّيْــرِ دِرَاسَــةٌ فِقْهِـيَّةٌ مُقَارنةٌ / The Sale of Loyalty and its Contemporary Applications: a Comparative Jurisprudential Study