That depends on the bench. Some urban benches do come with anti-theft bolts or tamper-resistant hardware, especially models built for parks, transit stops, school campuses, and streetscapes. Others don’t—so yes, with a standard wrench or socket set, someone can just unscrew the slats if the fasteners are ordinary hex bolts.
The difference usually comes down to the hardware spec. Many public furniture manufacturers offer security bolts as a standard or optional upgrade. Common anti-theft options include pin-in-hex screws, Torx security screws, tri-groove nuts, one-way clutch-head bolts, and breakaway shear nuts that snap off at a set torque once installed. These are all designed to be removed only with special tools or not removed easily at all.
If you’re looking at a specific bench, I’d check the product spec sheet or ask the supplier directly whether it ships with tamper-proof fasteners. In the field, you can also look for a small pin in the center of the bolt head—that’s usually a Torx security or pin-in-hex style. If the heads are smooth, domed, or have no normal wrench flats, that’s another sign of anti-theft hardware.
For high-traffic public areas, I’d recommend not relying on standard bolts alone. Even if the bench doesn’t come with anti-theft hardware, you can retrofit it with security screws and add a thread-locking compound or through-bolt the slats with tamper-resistant nuts underneath. That won’t make theft impossible, but it makes casual unscrewing far less likely.