TL;DR: might not be a "scam," but it's almost certainly a policy violation.
IMO it’s extremely unlikely that integrating a service like this would be compliant with CWS policy & enforcement. There are a couple of angles here to consider.
1. Single purpose policy
CWS has long had a “single purpose policy” that prohibits extensions from fulfilling multiple purposes. This is currently captured in the Quality Guidelines
policy. Changing a user’s default search provider is considered a distinct purpose, so if they ask developers to change chrome_settings_overrides.search_provider
that integration basically guaranteed to be in violation.
2. API Use
The API Use
policy requires that developers "use existing Chrome APIs for their designated use case. Use of any other method, for which an API exists, would be considered a violation." If the extension is exposing a general purpose search box, the extension is required to use chrome.search.query()
to perform the search using the user’s selected search engine.
The only situation I can see where it would be appropriate to perform a search using a different search provider is if the extension is exposing specialized search capabilities. For example, say I was developing an extension that helped users find, collect, reference, and cite academic papers. In that case, my extension could expose a search interface that enables users to search through academic journals and databases. In situations like this, I'd still encourage developers to clearly communicate to the user that a non-default provider will be used when performing the search.
3. User data handling
Integrating a search service like this likely violates a couple of the policies grouped under Protecting User Privacy
requires that user data only be accessed/collected for purposes directly tied to your extension’s purpose. Any data collected must be limited “to the extent required for a user-facing feature described prominently in the Product's Chrome Web Store page and in the Product's user interface.” See also Disclosure Requirements
If an extension exposed a search field that looked and seemed to behave like a standard search box, but took me to a different provider, I'd probably consider that to be Misleading or Unexpected Behavior