There is no such thing as "common sense". The cultural ethnic and personal diversities are too numerous as to exclude the possibility that either social or cultural norms will be known by all.
There are at this time approximately:
8 Billion people on the planet
195 Countries
7 Continents
2 Hemispheres
4,200 Religions
The Math:
8,000,000,000 x 195 x 7 x 2 x 4200 = 9.1728e+16 variations possible.
While all things are possible, not all are actually probable.
