You can see it that way, but you need to understand that if what you want from the Userinfo endpoint is to obtain claims about the subject... and to do that, you need to require scopes that map to claims (the openid scope does not map any claim) or you need to explicitly request the claims directly. An authorization request that only requests the `openid` scope should result in a Userinfo response containing only the user's `sub` (because that's a mandatory claim to return) but the OIDC server may chose to just fail the request.