No, they don't.
and some already don't such as theresa-may for example.
Theresa May is the current Prime Minister of the United Kingdom. Use this tag with the [united-kingdom] tag
I'm pretty sure nearly all of those were my suggested edits, I just used other excerpts as an example and it just became a routine from there. But it's pretty much personal preference as @Carpetsmoker mentioned.
I wouldn't edit it just to take that away though because you feel it's redundant, you'll run the risk of being rejected. It doesn't take anything away from the excerpt itself, nor' does it add anything. But if in the future you're suggesting tag excerpts by all means, don't add it in.