Salawāt upon prophets - for the reader, the writer, or both?

This should be an easy one... I am not Muslim, but I am fascinated by religion and try to read etc on the major religions. I am unclear, however, about the correct use of ṣalawāt ("PBUH" etc) when referring to prophets by name: is this requirement intended for the speaker/author, or for the listener/reader, or both? More specifically, as a non-Muslim, would it be actively inappropriate to include such? Obviously it would not serve me to offend a listener/reader by either including it inappropriately, or omitting it where the Muslim reader/listener would expect it. Even when used (or not) incorrectly, I expect most people would probably give me the benefit of the doubt and simply write it off (correctly) as ignorance, but: it would be good to have clear guidance in the correct usage by a non-Muslim (I am reminded of [the potential issues arising from *the salam*](https://islam.stackexchange.com/questions/1827/as-salmu-alaykum-for-non-muslims))