escalator etiquette

… feel my head touch my face … two steps back you’re in my space …

When you get on an escalator, can you stand on the step right behind someone or do you have to leave an empty step?

If you stand on the step right behind them, are you tailgating? Are you sending a message to them, asking them to move to the side so that you can pass? Are you just being rude? If they don’t move, are they being rude?