Etiquette taught that apologizing for accidental contact was mandatory in public

Evidence

Should you tread upon or stumble against anyone, do not fail to make immediate apology. Of course, you will not stare at nor point to people, nor carry umbrella or cane horizontally under your arm. — Lyn H. Lofland, World of Strangers_ Order and Action in…, 679

Categorization

• XREF: The apology-for-accidental-contact norm is the micro-level ritual Goffman analyzes as civil attention repair — relevant to the observing-self reading.