Do you mind if you receiving a letter written in red ink?

SEARU

Have　ｙｏｕ　　ｈｅａｒｄ　ｏｆ　‘blood－letter’？　In ancient times, if in emergency soldiers might tear off one piece of cloth from his clothing as paper and use his own blood as ink to write the might-be last letter to his relatives!
Even in　ｔｈｅ　modern　society，ｗｅchinese　should　ｎｏｔ　write　ｏｔｈｅｒｓ＇　ｎａｍｅ　ｉｎ　ｒｅｄ　ｉｎｋ，ｌｅｔｔｉｎｇ　ａｌｏｎｅ　ｓｕｃｈ　ａ　letter！　
Ｉ wonder if foreign friends also have similar saying？