Fortunately, buses are not invisible and you can look for a bus before crossing a street to gauge and control your risk of being struck by one.

... but you can still fail to notice one, and you can gauge and to some degree control your risk of being fined.

In fact, if you sell 10 hobby prototype boards to other hobbyists, you probably have a higher risk of getting hit by a bus on the way to the post office than you do of being fined.