Is showing up unannounced to someone's door something rude to do now?

I remember times when people would just knock on each other's doors and then people would be surprised when they see who was at their door, it seems now it's just an insane thing to do, no body just shows up at people's doors anymore, it's now a courtesy to call or contact a person first before knocking on their door, does anyone still just go around knocking on people's doors without letting them know? 🤔
Is showing up unannounced to someone's door something rude to do now?
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