Purchase an item. Hence, good Netiquette to buy. Given, free service to attract customers.
Purchase An Item When We Wi-Fi
Get something from the business. Businesses offer wireless internet service. Good customers use it.
As a result, make purchases. Then, a courtesy for the free service. In any event, customary.
Tips are always welcome from customers at coffee shops. There are exceptions to this rule. Some businesses offer loyalty cards.
Prove loyalty. Free to use the service. Kick in a little extra if possible.
This does not release users from the obligation to tip. Barristas at coffee shops work hard and deserve to be tipped like any other personal service.
In conclusion, make a transaction to use wi-fi in a cafe. It follows, be a good customer. And so, loyal.