This passage indicates that although the Sadducees strictly observed the prohibition of carrying from domain to domain on the Sabbath, they did not accept the Pharisaic device of Eruv designed to make possible the joining of domains and thus permit carrying in a common alleyway.
Rabban Gamliel said- Once a Sadducee lived with us adjoining the same alley in Jerusalem and my father told us- “Hurry and take all the vessels out to the alley before he takes things there and makes it forbidden to you.” 96 Rabbi Judah says this in different words- “Hurry and do all you have to do in the alley so that he does not take something there and make it unlawful to you.”
95. Trans. S. Berrin.
96. If a Sadducee who did not accept the law of Eruv lived in the alleyway, his refusal to participate made impossible the creation of a common domain to allow carrying in the common alleyway. But if the Sadducee did not make use of the alley on the Sabbath, then the others were permitted to carry in the common domain.