Assuming there's a user with ID
123456 logging into a web application where the randomly generated session identifier to be stored in the cookie looks like this
123456zXRL9DWpPtaAhkPzhemQZE5P5F (that is, prefixed with the user ID
******zXRL9DWpPtaAhkPzhemQZE5P5F), what are the potential security implications?
This would be to generate user identifiable access logs throughout various hops in a system, web servers, proxies etc. without the need to come up with schemes to pass around the user IDs.