Can we talk toilets?

Twice in the last two days I have walked into a public toilet only to overhear someone talking on their mobile phone as they sat in the stalls. Is this only a Japanese thing? I've never come across this anywhere else. Anyone else think it's a gross breach of etiquette (emphasis on the gross)? Anyway, next time you call me, if it sounds like there's a bit of an echo, you'll know why.