That's an excellent and very practical question! The answer isn't a simple yes or no, as it depends entirely on the specific context and who is managing the trash can.
In most public spaces like city sidewalks, parks, or transit stations, the standard metal or concrete urban trash cans are typically installed *without* permanent liners. Municipal maintenance crews usually supply and use heavy-duty plastic bags or liners during their scheduled collection rounds. They remove the full bag and replace it with a new one. So, as a pedestrian, you don't need to supply anything.
However, if you are asking for a commercial setting like a restaurant patio, apartment complex common area, or a private business district, the situation is different. When you purchase a commercial-grade "urban style" trash receptacle, it generally comes *as a unit only* – the liner is almost always a separate supply item. The responsibility for purchasing compatible liners (correct size and durability) falls on the property manager or business owner.
The key is to check the product specifications or your service contract. Some waste management companies include liner service with their commercial pickup contracts. For standalone cans, you'll need to measure the interior to buy the right size bags.
Best practice is to always use a liner. It contains liquids, simplifies cleaning, prevents waste from sticking to the interior, and makes the whole system more hygienic and efficient for the collection crew. So while the can itself may not come with a starter pack of liners, using them is highly recommended.