You can now limit access to features on Shopify POS by using the Limited Permissions feature with the Retail Package. You can see how to access the setting here:
When enabled, POS-only staff cannot:
Please update to the latest version of Shopify POS for iPad (if you don't have automatic updates turned on) by going to the App Store, choosing 'Updates' and selecting Shopify POS. This feature is available on Shopify POS for iPad, with the Retail Package.