Eiruvin 44b: One may form a wall out of people to permit carrying on Shabbos, but only if the people don’t realize they are being used as a wall. Once, Rava had some bottles that were lying in the street of Mechuza. As Rava walked home from his shiur, surrounded by talmidim, his assistants picked them up and carried them inside. Next Shabbos, they wanted to carry them in again, but he forbade them, because it was as if the people knew.

עירובין מד ע”ב: כאן לדעת, כאן שלא מדעת… הנהו זיקי דהוה שדיין בריסתקא דמחוזא, בהדי דאתא רבא מפירקיה אעלינהו ניהליה. לשבתא אחריתי בעי עיילינהו. ־ ואסר להו, דהוה ליה כלדעת, ואסור.

The Gerrer Rebbe once left a rare sefer in shul, and on Shabbos he wished to bring it home. So he told his gabbaim to announce that he would be walking home at a certain time. The Chassidim came to greet him, forming two lines along the street. The Rebbe, with the sefer hidden in his pocket, walked between the lines all the way to his house.

Source: R’ Eli Stefansky

Eiruvin 62a: All agree that we may rent a courtyard from a non-Jew (to permit carrying on Shabbos) even for less than a perutah. The disagreement is on whether we need a strong rental, or even a weak rental suffices. “Strong” means that the Jew must stipulate that he is allowed to fill the courtyard with chairs. “Weak” means that he need not make this stipulation.

עירובין סב ע”א: הוו יודעין ששוכרין מן הנכרי אפילו בפחות משוה פרוטה… אלא בריאה ־ במוהרקי ואבורגני, רעועה ־ בלא מוהרקי ואבורגני. פירש רש”י: למלאות החצר בספסלין וקתידראות אם ירצה.

When Rabbi Moshe Heinemann made the eiruv in Baltimore, he went to rent the rights to the city streets from the mayor.  The state’s attorney protested, “If you rent it to them, they could block the streets and stop traffic!” Chaim Wallin, an observant Jew who worked in the state’s attorney’s office, spoke up and said, “Don’t worry, they’ve been doing this for centuries in cities all over the world, and it never happened that they blocked traffic.”

Then Rabbi Heinemann and his colleagues went to the County Executive, since some parts of the eiruv were outside the Baltimore city limits, and he agreed to rent the county. Then one of the rabbanim suggested they rent from the State of Maryland as well. The logic of renting from city officials is that they are in charge of the fire department and police, who have the right to enter anyone’s house in an emergency. Here, he argued, the state is an even greater authority because they can declare a state of emergency and send the National Guard to anyone’s house. So they went to the office of the governor. “I’ll sell you the whole state of Maryland,” he said. “But I can’t take any money from you.” The rabbis were not sure what to do: the halacha requires that the streets be rented for some amount of money, even if it be less than a perutah. Then they came up with an idea: they made a plaque of appreciation for the governor, with a silver dollar framed inside. The governor accepted it and agreed to hang it on his office wall, where it could never be construed as a bribe.    

Source: Shiur by Rabbi Heinemann

[It seems from this story that they needed to use actual money, and giving an item worth money – like the plaque alone – would not have sufficed.

We also see that when the mayor objected that the rabbis might block the traffic, the rabbis did not promise not to do so. It was only a bystander who assured the mayor that they would not block traffic. This would seemingly be against Rashi, who explains that a “weak rental” means that the Jew need not ask for the right to block the street with chairs. Tosafos quoting the Aruch says that “weak rental” means without a written document. The Beis Yosef says that the halacha follows the opinion that a weak rental is enough, according to all explanations. Perhaps Rabbi Heinemann understood that one need not explicitly ask for the right to block the street, but one should not explicitly waive that right either.]

Eiruvin 44b: All those who go out to save lives may return to their places.

עירובין מד ע”ב: כל היוצאים להציל חוזרין למקומן.

וכתבו התוס’ שם הא דלא חשיב ליה בפ״ק דביצה (דף יא:) גבי הנך ג׳ דהתירו סופן משום תחילתן דזה אינו חידוש וכל הנהו צריכי כדאמרינן התם. ומזה למד הגר”מ פיינשטיין (או”ח ח”ד סימן פ’) דכל היוצאין להציל לא מיירי דוקא במלחמה שיש סכנה גם לאחר שנצחו, אלא אפילו בחכמה הבאה לילד וכדומה שלא יהיה עוד סכנה ובכל זאת התירו סופן משום תחילתן.

There is a doctor in Beilinson Hospital in Petach Tikvah who became observant 30 years ago. This is his story. A religious Jew called him on Shabbos to come and take care of his sick wife. When the doctor arrived at his door and saw that the man was religious, he said, “I’m afraid if treat her, you won’t pay me after Shabbos. Either pay me on Shabbos, or find another doctor.” The man said, “Yes, I’ll pay you on Shabbos.” So he treated the man’s wife, and then said, “You own me 250 shekel.” The man took out his checkbook and wrote a check for 1000 shekel. The doctor was puzzled, so the man explained: “The word אלף (1000) is only 3 letters while מאתים וחמשים (250) is 11 letters. I wanted to minimize my chillul Shabbos.” The doctor took the check and left.

On Thursday he called the man back and said, “I must tell you that I couldn’t sleep for the last few nights, I was in awe of your dedication for Shabbos. My wife and I have decided that we want to learn more about Shabbos. Can you teach us?” [This is based on the Tosafos in Eiruvin quoted above, which says that chillul Shabbos after the life has been saved is permitted because of the rule that “they permitted the end to facilitate the beginning”: if the people going out to save lives knew that they would not be allowed to return home, they might not go to save lives in the first place. This is the basis of R’ Moshe’s heter for Hatzolah members to drive home after a call – Igros Moshe O.C. 4:80. Here too, if this man had not paid the doctor, he would not go to help the next religious Jew who called him on Shabbos. Here the heter is more clear, since the doctor made that condition explicitly.]