Doesn't giving web crawlers different pages than the user facing UI get you kicked out of search engine indexes? The original ticket indicated different pages were served, not just QOS.
(I think) we're talking about pages served to logged-in users—i.e. the pages for files and folders in a given user's OneDrive account. Web crawlers wouldn't be able to reach those either way, so it (inconveniently from a fail-early perspective) wouldn't affect anything if the detection code does something stupid/crazy in the case of crawlers.