There's nothing wrong with wanting to know who you are talking with. One does wonder why someone insists on remaining anonymous.

Scenario: The Caribbean, back in the days of the Spanish Main.
Enter: English merchant ship, sailing merrily along, crew drinking rum and singing chanteys. Suddenly the lookout spots a sail on the horizon, but can't see an ensign yet. Ship goes on yellow alert (anachronistic Star Trek jargon). Then, strange ship comes close enough to identify.

English flag -- Stand down alert. Friendly ship. Everything's okay.
French flag -- France has been real iffy lately, don't know what they'll do. Maintain yellow alert.
Spanish flag -- Definitely hostile. Roll out the guns! Battle stations!
Jolly Roger -- Definitely hostile. Roll out the guns! Battle stations!
Unfamiliar flag, can't identify -- Maintain yellow alert, see what they do.
No Flag at All -- Now that's really suspicious! Could be anything! Roll out the guns! Battle stations! But wait and see what they do. But if they fire on us, blow the bugger out of the water!!

. But then, a wise captain might chose to pile on all sail and outrun it. Other than noting its existence and taking appropriate action, he just ignores it.

Don (just finished reading Captain Blood again) Firth