You'd think a person who can shower, shave, dress himself, and drive to town wouldn't need to be told how to operate stairs. Maybe STEP UP is a coy sales tactic urging you to buy something beyond your means and boost your social position. Back home while putting up the groceries, you really get a talking-to. It's a kindly-worded phrase, but it doesn't make sense. It's less confusing.
Some commands are downright insulting.
People that would spit in a taxi probably couldn't read the sign, and would ignore it if they could. That sign should go. Although there may be some individuals who don't understand the principles of octane, anyone who'd light up in a cloud of gas fumes would probably deserve everything he got. Mother Nature's cute little way of weeding out the bad apples. Dumb signs like this are there only to protect the businesses that put them up.