Never provide your card number as proof of age. Keep a record of your transactions. Pay with your credit or check card. Take your time and have fun. You are not liable.
Consumer protection varies from country to country and from region to region.
Merchant banks are responsible for any charge-backs. Generally, these charges are passed from the bank back to the merchant. In your best interest, Visa's cardholder protection policy requires all banks issuing Visa products to provide provisional credit for losses from unauthorized card use within 5 business days of notification of the loss. However, many major financial institutions will provide provisional credit within 24 to 48 hours after the loss is reported. Overall card fraud continues to decline, but the Internet is a relatively new area and Visa has always been at the forefront with opening new markets and making them safe for you.