You may read on Snipcart's documentation that Snipcart will 'crawl' a site when an order is placed to verify that a product's price and other details have not been changed by the visitor.

This add-on provides such information through a particular URL that is not restricted by permissions, it is always available.

Therefore you may used concrete5's permissions to control the access to product blocks (through permissions on pages or the blocks themselves).

This allows you to create different sets of products for different user and user groups, for wholesale ordering, member pricing, etc.