The quotation I cited is reproduced verbatim from the contract.
As for allowing another person to use the phone for a short time — my understanding is that this clause is not meant to prohibit that. It seems that the intent of the clause is to prevent the transfer of substantive rights, such as ownership or ongoing control, to another person — for example, to my son — and not momentary or occasional use.

From here an internal contradiction arises that creates hesitation: on the one hand, these are the terms written in the contract; on the other hand, the wording of the contract itself seems unreasonable and at times even detached from reality. The question is whether the halakhic obligation requires keeping the contract “as written, word for word” (AS IS), or whether there is room for discretion, with interpretation based on what a reasonable person would do in this situation.

If the conclusion is that there is room for discretion, then it can be understood that it is permitted to transfer the SIM card for use by a third party (such as a son), and it is even permitted to connect the device to a computer — since it is clear that the drafter did not really insist on these points. If he did insist on their literal fulfillment, that would deter customers and hurt the business, so it seems they were included more as CYA than as a binding instruction.

I already answered that, and I’ll now sharpen an important point. There is common sense, and it is part of legal interpretation and halakhic interpretation. There is no point in being a halakhic formalist with respect to the law and to contracts in general. Interpreting a contract also depends on common sense, and it is important to use it. This reminds me of what I once wrote about the principle that the law of the land is the law. There are people who treat the law with holiness as if it were Jewish law, since according to Jewish law the law of the land is the law. And so the law becomes a sacred text that one must scrutinize carefully so as, Heaven forbid, not to violate it. This is nonsense. One should obey the law the way a reasonable secular person obeys it. And if there is a road where the maximum speed is 90 and you drove 100, no disaster has happened. You certainly did not commit a halakhic transgression. Jewish law also has common sense, and certainly when Jewish law gives force to external principles (such as civil law). In such a situation, one should interpret them and relate to them the way a reasonable secular citizen does.
Another example: the honor that must be given to the government. There are those who cite the obligations toward a king in Jewish law and argue that they should be applied to a president or prime minister, etc. That is of course complete nonsense. We are talking about a ‘democratic king’ (not a monarch), and the attitude toward him is determined by what is accepted in a democracy. There is no need to turn the law into sacred letters and to parse them formalistically.

I agree with the Rabbi’s words on an intuitive level, but the question arises: where exactly is the boundary of “common sense”? It is clear to me that my discretion is not identical to the Rabbi’s, and I also know quite a few people who, in my opinion, start thinking in ways that are not exactly straight.
As an example, one can bring up Netflix subscriptions: the company offers a family subscription defined for users living under the same roof. In practice, people I know share the subscription with family members who do not live in the house, for example a child who got married and moved elsewhere but still uses the parents’ account. On the one hand, one can argue by common sense that Netflix has difficulty enforcing this or perhaps cannot really enforce it, and therefore it is reasonable to share the account within the family. On the other hand, this is contrary to the terms the company itself set.
From here a substantial difficulty arises: if we adopt an approach according to which every clause has a flexible interpretation, then in practice every contract loses its force, since everyone can interpret the commitment however he wants

The discussion has lost its meaning. You are expecting a formal definition of common sense. That is exactly what common sense means: beyond formal thinking.
That’s it. I’m done.

Michi, I think all these irritating questions that have recently been coming under the name “The Questioner” should be replaced and written as “Rabbi Yirmiyah,” and the one answering under the name “Michi” should be changed to “Hillel.” If I didn’t hesitate, I’d say this is actually trolling, but the marks of “foolish piety of the Tzelniker type” are evident in the writer’s words, so I’m not convinced it’s sophisticated trolling.