Scenario

User accidentally specifies a custom scope in package.json, but wants to compile as a Model project. roblox-ts will infer this as a Package project due to the custom scope and emit local TS = _G[script] for RuntimeLib usage.

The user can workaround this by:

1. Specifying --type Model in CLI args
2. Removing custom scope from package.json

I think a diagnostic makes sense here. There's no reason you'd want to compile a Package project and include RuntimeLib.lua in your default.project.json. This would only ever result in either packages accidentally publishing with a RuntimeLib.lua or non-package projects compiling with local TS = _G[script] when they shouldn't.