Making the visitor put up with your bot because you don't like someone else's is just bizarre to me. I disable js by default, so Ive been seeing this more and more. It's all rubbish these days.
Anubis author here. I have been working on a no-js approach. I just have to be careful so that the scrapers don't just implement it and bypass it forever.
go-away has one, it only works in browsers that follow meta refresh though.