此男有妻请勿勾引此女有夫请勿调戏
[cĭ nán yŏu qī qĭng wù gōu yĭn cĭ nǚ yŏu fū qĭng wù diào xì]
This man has a wife please don’t seduce him; this woman has a husband please don’t flirt with her. These phrases put others on notice regarding relationship status, expressing seriousness against third-party interference.