In journals using customized comment pages, you can also view comments without threads -- in the exact order they were posted -- by adding ?view=flat to the end of the URL (or &view=flat if the URL already contains a question mark).
It may be a good idea to mention fallback=s2 along with that, since ?view=flat depends on S2 styling. You don't necessarily have to have customized comment pages; you can use fallback=s2 for that. I suggest adding: "In the journals that don't have customized comment pages, you can append the URL with ?view=flat&fallback=s2." or something like that.