Moral Dilemma 1:

On a visit to Tesco, who have just announced profits of £580m you see an air conditioning / heating unit reduced from £299 to £199. You had been looking to buy one. You decide to buy it
and take it to the self service checkout. When you scan the box it comes up at £1.99.
What do you do?

בבא קמא קי״ג ב:י׳

אמר שמואל טעותו מותרת כי הא דשמואל זבן מכותי לקנא דדהבא במר דפרזלא בד' זוזי ואבלע ליה חד זוזא

Bava Kamma 113b:10

The Gemara adds: Shmuel says that it is permitted to financially benefit from a business error of a gentile, i.e., it need not be returned. The Gemara notes that this is like that incident where Shmuel purchased a golden bowl [lakna] from a gentile in exchange [bemar] for the price of an iron bowl, which was four dinars, and Shmuel included one additional dinar in the payment so that the gentile would not realize his mistake.

משנה תורה, הלכות גזילה ואבידה י״א:ד׳

טָעוּת הָעַכּוּ''ם כַּאֲבֵדָתוֹ וּמֻתֶּרֶת. וְהוּא שֶׁטָּעָה מֵעַצְמוֹ אֲבָל לְהַטְעוֹתוֹ אָסוּר:

Mishneh Torah, Robbery and Lost Property 11:4

A mistake in accounts made by a gentile is considered like a lost article, and it is permissible to benefit from it. This applies if he makes the mistake himself. It is, however, forbidden to cause him to make a mistake.

משנה תורה, הלכות גזילה ואבידה י״א:ה׳

כֵּיצַד. כְּגוֹן שֶׁעָשָׂה הָעַכּוּ''ם חֶשְׁבּוֹן וְטָעָה. וְצָרִיךְ שֶׁיֹּאמַר לוֹ יִשְׂרָאֵל רְאֵה שֶׁעַל חֶשְׁבּוֹנְךָ אֲנִי סוֹמֵךְ וְאֵינִי יוֹדֵעַ אֶלָּא מַה שֶּׁאַתָּה אוֹמֵר אֲנִי נוֹתֵן לְךָ כְּגוֹן זֶה מֻתָּר. אֲבָל אִם לֹא אָמַר לוֹ כֵּן אָסוּר שֶׁמָּא יִתְכַּוֵּן הַגּוֹי לְבָדְקוֹ וְנִמְצָא שֵׁם שָׁמַיִם מִתְחַלֵּל:

Mishneh Torah, Robbery and Lost Property 11:5

What is implied? A gentile made an account and made an error in a Jew's favor. The Jew must tell him: "Look, I am relying on your account. I know only what you tell me." In an instance like this, if the gentile does not correct himself, it is permitted to take advantage of his error. If, however, one does not tell him this, it is forbidden. It is possible that the gentile's intent is to check the Jew's honesty. By keeping the money, one may cause God's name to be desecrated.

מגיד משנה על משנה תורה, הלכות גזילה ואבידה י״א:ד׳:א׳

טעות העכו''ם. פסק כרב כהנא דעבד הכי פרק הגוזל ומאכיל. מיהו מהך דשמואל ורבינא משמע התם דאין צריך שיאמר לו ישראל ראה שעל חשבונך אני סומך ורב כהנא דעביד הכי ממדת חסידות:

Maggid Mishneh on Mishneh Torah, Robbery and Lost Property 11:4:1

...

The consumer argued that she had simply paid the asking price.
In evidence, she denied knowing the correct price, registration or mileage of the vehicle and further claimed she did not know her budget. Her denials were in despite of the fact she had managed to negotiate on her part exchange and secure a reduction on the asking price, which she did not know?!
Suffice to say, the judge was having none of it and described her evidence as “completely implausible”.
The judge was also directed to Chitty on Contract and in particular, the important and well-established legal authorities of Hartog v Colin and Shield [1939] 3 All ER 566 and Smith v Hughes [1871] LR 6 QB 597.
The judge accepted our member’s evidence unreservedly that there was a price in mind and the consumer knew the price and, on that basis, there was no good reason why she should not be bound by the intended price rather than the error.
This finding was supported by the fact that within hours of the sale, our member contacted the consumer and asked for the correct amount. He even offered to return her part exchange and refund her if she was not happy with the correct price, so there would have been no loss to her. Instead, she declined such reasonable offer and sought to take advantage of our member’s error.
Rightly, judgment was given for our member, as claimed.

Steven Dansky