438. The rules as regards those who are not strangers are: (a) inhabitants and residents are subject to the diocesan, provincial, and other particular laws of their territory (Canon 13, Sec. 2); (b) the homeless are subject to the local laws of the territory where they are present (Canon 14, Sec. 2). 439. The rules for strangers with reference to general laws (Canon 14, Sec. 1, n. 3) are; (a) a stranger is obliged to follow these laws, if they are observed in the place where he is, even though they are not in force in the place of his domicile or quasi-domicile; (b) a stranger is not obliged to observe general laws, if they are not in force where he is, even though they are in force in the place of his domicile or quasi-domicile. Thus, the general law of abstinence on Friday does not oblige one who is travelling in a place where the law has been suspended, even though he would be obliged by it at home. The traveller would do better, however, to keep to the practice of his home. 440. The rules for strangers with regard to the particular laws of their own domicile or quasi-domicile (Canon 14, Sec. 1, n. 1) are; (a) they are obliged in two cases--first, when those laws are not territorial but personal and obligatory on them everywhere (as is the case with the statutes of religious superiors), and secondly, when the violation of a territorial law would be harmful in its own territory (as when by fiction of law one must be considered as present on account of the law of residence); (b) they are not obliged in other cases. Thus, if one is travelling on a feast-day that is a diocesan holyday in one’s home diocese, but not in the diocese where one is, one is not obliged to hear Mass. 441. The following are the rules for strangers with regard to the particular laws of the place where they are: (a) they are obliged in two cases--first, when natural law itself requires that a territorial law be observed by all, and secondly, when the Church includes strangers among those who are subject to a territorial law; (b) they are not obliged in other cases. Thus, if a person is travelling on a feast-day that is observed as a holyday of obligation both in his home diocese and in the diocese where he is, but not as a general holyday of the Church, he is not obliged to hear Mass; for the law of his home diocese does not bind him, since he is out of its territory, and the law of the diocese where he is does not bind him, since he is not a subject of that law. 442. The natural law requires that strangers should conform themselves to local laws in the following cases: (a) when non-observance would be a cause of scandal, which the natural law commands one to avoid. In this sense we understand the rule of St. Ambrose: “When you are at Rome, do as the Romans do.” Hence, if a stranger would cause real scandal by eating meat on a local day of abstinence, he would be obliged to abstain from it;