Tag discussion: pipes, drainpipe, warp_pipe

Would you give me advice about these kind of tags?
Aside from tube tag, we have drainpipe, warp pipe and pipes.
(I have merged concrete pipe tag into drainpipe.)

tube should probably be strictly for flexible tubes (though I see lots of diploma tubes under it, which need their own tag).

I prefer concrete_pipe over drainpipe for the thing in post #211726, but it should definitely be tagged separately.

pipes->pipe looks like a pretty standard plural->singular alias. Edit: Oh wait, looks like pipe is the thing you smoke. Uh, I dunno, then. Maybe the tube/pipe distinction isn't so important after all?

And warp_pipe seems fine as it is.