Most of these fence panels are bi-facial, i.e they have panels on both sides. They catch light reflected from the ground/snow/etc. They cost a bit more than single pane panels, but not a lot more. Like 15-20%.

You dont get nearly double the power, but they tend to work a bit better then single panels facing the sun because solar panel efficeny degrades with heat. When the sun is at its strongest, traditional roof mount panels take a significant efficiency hit. Because bifocal labels are generally positioned more flexibly, they have much better cooling that compensates for their bad angle.

Hard disagree about vandalism. You will likely never have an issue, and even then the individual panels aren’t that expensive to replace. A wood fence would likely cost more to cover the same surface area of one 7ft x4 ft panel.