Guessed it by the headline...
Thanks for helping educate about this interesting fact.
The response about "ridiculousness" is not surprising either. Having kept Shabbat for many years, we'd check our local eruv and see whether it was still in tact and may a determination on carrying objects.
There are some groups within Orthodox Judaism that don't accept an eruv at all or have different customs. For example, there are arguments among scholars about whether gloves can be worn on Shabbat in the winter, lest one remove a glove to shake a fellows hand, in which case he'd be carrying it.
Others might go the route of fashioning objects into clothing that can serve as a dual purpose during Shabbat. For example, a belt buckle that also serves as keys for one's house.
Yes, to an outsider, these rules ridiculous. Even to insiders they do as well, but there is a certain beauty in the exercise of examining laws and trying to make convincing arguments to test their limits.