Your system wouldn't prevent detection as a simple fixed cookie on the landing page and a redirect on a robot prohibited page, with js on this page expecting th

Your system wouldn't prevent detection as a simple fixed cookie on the landing page and a redirect on a robot prohibited page, with js on this page expecting the cookie and you get yourself a detection mechanism. (Note that you could also check server side on the redirection page) I believe (but I cannot formally prove it) that it's actually impossible to prevent detection. It's a bit similar to private browsing mode (which in that case should in theory not be detectable) but has revealed to be a challenging problem.