Guest Wi-Fi is a wireless network offered to customers, kept separate from the business's own systems. It is often paired with a captive portal, a splash page where users accept terms or enter details before getting online.
It works by creating a separate network name (SSID) mapped to its own VLAN or isolated network, so guest devices can reach the internet but not tills, printers, cameras or file shares. Client isolation stops guests seeing each other, and bandwidth limits stop one user flooding the connection.
Cafes, restaurants, hotels and shopping centres use it as an amenity, to collect opted-in marketing contacts, and to extend dwell time. Retail stores use it less often, but some use it for in-store apps and analytics. Keeping the guest network on its own connection or bandwidth cap also protects speed for card payments and online ordering during a rush.
The most serious pitfall is putting guests on the same network as the POS, which can expose payment systems. Also consider bandwidth sharing, content filtering, how long details are kept, and consent for marketing under privacy and spam rules. Check current requirements before collecting emails or phone numbers.
Done properly it is a customer benefit; done badly it is a security hole and a drain on the business's main internet link.