If you install a free plugin or theme integrated with Freemius on your client’s site and you are not sure whether they are willing to share any data for usage tracking, click the Skip button, and no data about your client’s site or your WP admin user will be tracked.
If you are installing a paid product that is integrated with Freemius and you activate a license key, no information about the client or the logged in WP admin user will be collected. The license key and the other data mentioned in the table above (site URL, PHP & WP versions, etc.) will be securely collected.