The Rebbe and Eruvin Established in Other Communities
Chabad communities have accepted eruvin where the local conditions and local psak allowed them. Each such eruv belongs to its own streets, boundaries, population, and Rabbonim; it does not decide the status of Crown Heights.
Kfar Chabad
Kfar Chabad has long had an accepted local eruv. Its scale, streets, boundaries, population, and rabbinic authority are different from Crown Heights.
Someone accustomed to carrying there still needs the local psak when visiting another community. The existence of the Kfar Chabad eruv shows that the question is the validity and acceptance of a particular enclosure, not opposition to the mitzvah of eruv.
Rockaway
Rabbi Asher Herson's account describes a local eruv question handled through the Rabbonim responsible for that community. The relevant authority and physical conditions remained local to Rockaway.
Its use in the Chabad discussion is therefore limited and practical: a decision for Rockaway does not authorize an eruv in Crown Heights, just as Crown Heights does not decide the route of a different community.
Miami
Rabbi Shmuel Zajac relates that Rabbi Shmuel Tuvia Stern told the Rebbe he had made an eruv in Miami. The Rebbe answered by asking whether Miami had shishim ribo.
The question goes to the status of the city before the poles and wires. The full Yud Shevat 5743 farbrengen is preserved, while the brief exchange is used in Rabbi Zajac's name because a reliable timestamp has not been isolated.
Melbourne and Doncaster
The Melbourne response requires a thorough investigation by qualified local Rabbonim and says that an eruv should be made only in secrecy. A later answer leaves the Rabbonim's public course of action to their judgment.
The Doncaster response concerns whether Rabbi Mordechai Zev Gutnick should enter a complicated local eruv matter. Each answer stays with the people and conditions of its own place.
Crown Heights has its own ruling
An accepted eruv elsewhere does not supply Crown Heights with walls, change its streets, establish its communal arrangements, or replace the psak of its Beis Din.
Rabbi Yehuda Leib Groner gives the Rebbe's Crown Heights wording directly, and the local Rabbonim prohibit reliance on the publicized route.