Imagine a list of lists similar to this:
var list = [
{ name: \'group1\',
items: [ 1, 2, 3, 4, 5 ]
},
{ name: \'group2\',
items: [ 1, 2, 3, 4
I consider it to be just like id attributes. They are supposed to be unique, but you can actually re-use it in the same page and you can still select it. That said, just because it can be done doesn't mean it should be done.
I would recommend against it.