There are major differences in BR etiquette in various cultures.
For example, it is not uncommon in Rome, Italy, to be approached by a beggar at the precise moment you start urinating in a public BR. Generally, people tend to walk away quickly when approached by Roman beggars on the street, but one just cannot walk away in this situation.
Every time I heard someone complaining about this, the person to whom it happened was a priest wearing his collar, and urinating in a public BR near the Vatican. The beggars apparently choose priests because a priest cannot quite swear at the beggar and is more likely to spare a couple hundred lire just to avoid public embarassment.