Are there any fatwas regarding the etiquette of visiting, and specifically, is there a text in the Quran or Sunnah that clarifies the ruling on an invited person attending a public event through another invited person, rather than through the host themselves, in order to avoid embarrassing the host and the invited person?

Among the etiquettes of visiting brethren is that it should be after seeking permission and at appropriate times, as Allah the Almighty says: "O you who have believed, do not enter houses other than your own houses until you ascertain welcome and greet their people..." {An-Nur:27}. Also, there are inappropriate times for visiting, such as times of privacy, as Allah the Almighty says: "O you who have believed, let those whom your right hands possess and those who have not reached puberty among you ask permission of you three times: before the dawn prayer and when you put aside your clothing [for rest] at noon and after the night prayer..." {An-Nur:58}. One should not attend events without a specific invitation unless the invitation is general, or if custom dictates it. If a person attends without an invitation, they must seek permission at the door before entering.