It's good to consider this but... Plenty of sites expose user ID as a regular integer. In some cases you might want to avoid this (leaking user count to competitors etc), but I have never heard about anyone calling this a vulnerability.
It's referred to as an "Insecure Direct Object Reference" (IDOR) vulnerability. In many cases it is not actually a vulnerability, however, when an application contains sensitive information and lacks authorization or rate-limiting it can be exploited to enumerate the entire database.
When I first joined $company, HR sent me a SharePoint document with a numerical ID. Incrementing or decrementing the ID allowed me to view personal information of other employees including their pay.
