The New York Times has a story about three lawsuits that have been filed over the erection of an eruv, or ritual boundary, for Orthodox Jews in the Westhampton Beach area of New York. It gets some important details wrong. Let's look at the beginning:
Every Saturday, Eugene Milanaik, a nurse anesthetist, walks more than five miles back and forth between his Orthodox synagogue and his weekend house on Dune Road. When it rains, he gets soaked, because he cannot carry an umbrella. When his 3-year-old grandson is in town, as he was last weekend, his wife must stay home, because she cannot push his stroller.
Life would be much easier, in Mr. Milanaik’s view, if Westhampton Beach would finally permit a series of narrow plastic strips, known in Hebrew as lechis, to be placed on the village’s utility poles. The strips would create an eruv, a ritual boundary that would allow those Orthodox Jews who do not push or carry things outside the home on the Sabbath to do so when within the eruv’s perimeter.
Technically, the strips don't create the boundary -- there needs to be a string between them. Anyway, I think it's safe to say that this passage leaves the impression that it would be permissible to carry an umbrella if the eruv were created. But is that Orthodox practice? Here's Rabbi Ari Enkin:
It is well-known that one is forbidden to use an umbrella on Shabbat. This is because the use of an umbrella is considered to be a violation of the melacha of “boneh”, the prohibition of erecting any type of tent, structure, or protective covering. In fact, the use of an umbrella might even be a violation of a number of other Shabbat prohibitions, as well. An umbrella may not be used on Shabbat even if it was opened before the start of Shabbat. This is primarily due to the prohibition of ma’arit ayin (“the appearance of a sin”) lest onlookers be led to believe that one had opened the umbrella on Shabbat itself. ....
Even though there have been authorities in the past who supported the use of umbrellas on Shabbat, the familiar ban on using them is one which has been universally accepted. In fact, the Chafetz Chaim writes that “one who is careful with his soul will refrain from using them”. Not only is it forbidden to use an umbrella on Shabbat, but they are muktza and may not even be moved. Furthermore, our sages decreed that one should avoid assembling all forms of tents and canopy-like structures on Shabbat, even permitted ones, lest it lead to handling forbidden ones. Nevertheless, one need not overly rebuke those less-learned who use an umbrella which was opened before Shabbat. One may open and close garden umbrellas on Shabbat which are permanently implanted into the ground or some other base.
The next error is also striking.
Eruvim are an arcane matter to most people, but they are not unusual: much of Manhattan lies within the boundaries of an eruv, as do scores of Orthodox communities around the country.
“If other towns have it, we should have it,” Mr. Milanaik, 68, said on Friday, after stashing a backpack filled with his Sabbath essentials — two prayer books, a prayer shawl, and phylacteries — in a plastic bin at the Hampton Synagogue, so he would not need to carry them on the Sabbath. “I’m getting by without it, but it would be nice. It’s like being handicapped.”
Phylacteries are traditionally called tefillin. As Tablet magazine editor Yair Rosenberg writes, "They're not worn on the Sabbath, and are in fact forbidden to be touched. So no one would carry them." More here and here. I'm not sure it's helpful to refer to eruvim as an arcane matter -- secret, mysterious or obscure. They may not be simple, but the rules are spelled out fairly clearly.
Bethany Mandel, who brought all these problems (from just the first four paragraphs of the story!) to my attention, suggests that readers curious about this story instead view this Daily Show segment called "The Thin Jew Line" on the matter, if they're looking for accurate information.