Yes, but with a big caveat. Some cities do use heavy-duty urban trash cans as temporary parade barriers, especially when the bins are sturdy, weighted, locked, and placed as part of an approved crowd-control plan. They can help guide spectators, protect sensitive areas, and add a visible edge to the route without bringing in extra barricades.
That said, ordinary trash cans are not a safe substitute for proper crowd control barricades. Standard municipal waste bins can tip over, roll, hide hazards, or leave dangerous gaps, and they may block emergency access if they are not carefully spaced. For parade safety, any use of urban trash cans as temporary parade barriers should be approved by event organizers and public works staff, secured in place, marked clearly, and monitored throughout the event. So the short answer is: sometimes, but only when they are heavy-duty, secured, and used as a backup—not as the main barrier system.