(b) If one rides without payment, but uses the ticket of another, there is no injustice if the rules of the company permit this (e.g., A buys a round-trip ticket, but gives the return ticket to B), but there is fraud if the rules of the company and the agreement of the purchaser make the ticket non-transferable (e.g., B uses the half-rate ticket which A had received as a personal privilege from the railroad company).
1908. Small Thefts Which Amount to a Large Sum.—Small amounts stolen may accumulate into a large amount. This happens in the following ways: (a) the thief takes small sums on different occasions from the same person or from different persons, and continues at this until he has stolen a considerable amount; (b) the thief conspires with other thieves to steal on the same occasion from one person or several persons, and, though the sum he steals is small, the sum taken by the whole group is considerable. Similarly, petty damages or vexations may accumulate into a mortal injustice. Thus, if Claudius, aiming to break down the health, sanity, success, reputation, business, etc., of Balbus, plans and carries out a systematic campaign of small injuries daily repeated for years, Claudius is guilty at least in purpose of serious damage.
1909. Small thefts that grow into a large theft are mortally sinful in the following cases:
(a) they are mortally sinful by reason of the previous intention when one steals a little now and a little again, but has it in mind from the outset to steal a total sum that will be grave matter, or when one conspires with others to steal a notable sum although one’s own share will not be a notable amount. In these cases the purpose is to commit a grave injustice, either against an individual (if all is taken from one person) or against society (if portions are taken from various persons), and hence one is internally guilty of grave sin, even though one has not yet performed it externally. Examples are merchants who use false weights and measures, or who adulterate their commodities with small portions of water, etc., and thus make large profits by minute cheating;
(b) they are mortally sinful by reason of the subsequent intention when one had no purpose to steal a large amount, but adverts to the fact that a small theft here and now committed will constitute grave matter if added to previous petty thefts, or that the amount of stolen goods now possessed is large, and nevertheless resolves to go ahead with the theft or to retain the stolen goods. This does not mean that a number of venial sins coalesce into a mortal sin (see 189), but only that the object of a sin which is slight in itself becomes serious on account of the circumstance that it is morally connected with previous sins. The last act in a connected series must not be taken singly, but in connection with the acts that precede, as is seen in the violation of a fast or in omission of parts of an hour. In the cases now considered, therefore, grave injustice is actually and purposely done, and mortal sin is committed, even though there was no thought of this in advance.
1910. The case of young men who are educated free of charge in the expectation that they will go on to the priesthood and who do not persevere.—(a) If they act in bad faith (i.e., if they enter the college or seminary merely to get their education, or to avoid work, or if they remain after they have abandoned thought of the clerical state), they are guilty of theft and bound to restitution.
(b) If they are not in bad faith (i.e., if they wish to try out their vocation, or if they begin with the intention to persevere), they are not guilty of injustice. This is true, even though they are rejected on account of idleness or other faults, provided there was no intention to defraud.
1911. In the following cases small thefts which added to others make a large sum seem not to be the cause of grave loss, and hence not mortally sinful:
(a) the small theft of one person following on the small thefts of others, when there is no bond of example, advice, conspiracy, etc., to unite the various thefts; for none of the thieves can be held responsible for the part of the loss caused by the others. Example: Titus, knowing that Balbus has been cheated by various persons to the amount of $9 and that $10 will be a serious loss to Balbus, proceeds to steal $1 from Balbus:
(b) the small thefts of several persons who steal together, and who influence one another only by example; for example is an occasion, not a true cause of the imitator’s act (see 1447, 1763). Example: Sempronius and Claudius go into a store together and find that there is no one around. Sempronius thereupon steals a number of articles and leaves. Claudius notices this and steals other things, which will make the total loss serious.