That's a great and very practical question! I've wondered the same thing myself when walking through a park on a sunny day. The short answer is: yes, stainless steel trash bins can get quite hot to the touch in direct, intense sunlight, but it's rarely a major safety hazard under normal use.
Stainless steel is a highly reflective metal, but it's also an excellent conductor of heat. In full summer sun, the surface temperature can easily exceed 140°F (60°C), which is certainly hot enough to cause discomfort or a minor burn if touched for more than a few seconds. You'll notice this most on the lid and the upper, sun-exposed sides.
However, modern urban design usually accounts for this. Many public bins are placed in partially shaded areas or under trees. Their design also helps—the curved surfaces and often polished finish help reflect some radiation, and the heat dissipates relatively quickly once the sun moves. The areas people actually touch to lift the lid (often the handle or a pedal) are usually designed to be less conductive or are shaded by the lid itself.
For waste management crews, it's a known issue. They typically handle bins in the early morning or use gloves. For the general public, the key is simply to be aware. On a scorching day, use a napkin to lift the lid or opt for a pedal bin if available.
So, while they do get hot, it's a managed aspect of their functionality. The benefits of stainless steel—durability, corrosion resistance, ease of cleaning, and a sleek appearance—often outweigh this thermal drawback for city planners. The heat concern is real but manageable with a little common sense.