When to help a travel customs mistake — is correcting strangers' slipups rude here?

Last week at a border checkpoint in the Black Sea region, a passenger ahead of mine attempted (futilely) to complete an inbound customs申报 manually using last year’s edition. The local passenger didn’t appear aware they were using an expired form. Rather observe in silence, I approached and quietly mentioned the revised format (pointedly showing both the date block on the top left and the official print run stamp). My effort was meant as neutral guidance — yet afterward several other citizens present began murmuring about foreign 'interference' with local autonomy at customs posts.

This left me with lingering confusion: culturally, where lies the boundary between helpful intent and unnecessary overreach? If a foreigner notices a locals unintentionally violating regulations due sheer misunderstanding — is it better to let the situation proceed (accepting potential later repercussions)? Or is offering technical clarity inevitably perceived as an encroachment upon cultural norms of self-guided travel practice?

Specifics matter. This incident involved a simple administrative document rather than complex human choices (e.g. lost directions). I did not attempt to dictate outcomes just highlight objective discrepancies from rules — yet locals implied I disrupted natural consequences they themselves should have sorted. Could this reflect unspoken customs about authority? Please share relevant experiences: in this globalized moment, how often is 'help ' misunderstood abroad this way when crossing international travel stages?