If [this](https://github.com/json-schema/JSON-Schema-Test-Suite/blob/468fa788ca2053a69815c43abc500e044086120c/tests/draft4/optional/format.json#L39) is invalid and [`id`is supposted to be a `uri` (and not a relative reference)](https://github.com/json-schema/json-schema/blob/cc8ec81ce0abe2385ebd6c2a6f2d6deb646f874a/draft-04/schema#L30). Then why is [this](https://github.com/json-schema/JSON-Schema-Test-Suite/blob/17a47459654fcc8094a31180de4496ec298d8c07/tests/draft3/optional/refRemote.json#L57) valid?