Throw exception on suspected incorrect arguments.

This can only be done if we attempt to match the connect-oauth-key,
as a simple string might otherwise be an incorrect arg. All auth
keys passed as the last arg (to any method) must be of the form
/^(?:[a-z]{2}_)?[A-z0-9]{32}$/. This also involves using correct
auth-keys in all the relevant specs instead of stubs like auth123.