Excuse me.

That's all it means. Excuse my impertinence, presence, gaul, mere existence; I need your attention. Many languages have this overloaded phrase and use it just as a Brit would "sorry". It's formal deference. It's polite.

And it's not like we don't also shout "Oi!" when we need to determine whether or not some brigand possesses a licence for whatever it is they're doing.