I have no idea why they Amish would refuse to put slow moving vehicle (SMV) reflectors on the back of their buggies. Its extremely dangerous for everyone on the road at night without them.
Other farmers use SMVs and they generally have lights to boot.
We have Amish communities here in Hardin County, which is about 150 miles east of where this occurred. The Amish here all display the orange warning triangles on their buggies.