From personal experience, it seems that chassidim generally are opposed to dual-sided wearing of items, while completely accepting the single-sided equivalent. Examples include:
- Backpack vs messenger bag, satchel, handbag
- Child carrier vs carrying a car seat using the handle
- Headphones vs telephone headsets ("Bluetooth®")
I've lived for over 10 years among chassidim, and do not remember ever seeing any chassid use the dual-sided implements, while the single-sided ones are a daily sight. My wife's Satmar/Malachim grandfather even promptly got us a stroller when he saw us using a child carrier!* I asked the son of a chassidic rebbe, who agreed that chassidim do not use such items, but was unable to explain it.
One may think that it stems from an aversion to modern trends, but the Bluetooth example would contradict this.
Where does this behaviour come from?
*It was clear that he was unhappy with the carrier, even though we were traversing stairs daily, using public transportation, and carrying luggage – all activities for which a carrier is more convenient than a stroller.