Bris
Question
Why do people not “invite” others to a Bris?
Answer
Shalom!
Thank you for your question.
The reason for this is based on the teaching that one who does not attend a simcha (seudat Mitsvah) to which one was invited, such as a bris , deserves to be excommunicated. As such, one merely “informs” people where and when a brit will take place.
Nevertheless, even if one was formally invited to a bris there is no true obligation to attend, since the transgression of not participating when invited is only for someone who is at the seudah and doesn't eat. Therefore, Harav Fried Shelita says that one may be lenient and leave before the meal begins.
SOURCES: Pesachim 113b, Rashbam; Rema, YD 265:12; Pitchei Teshuva , YD 265:18; Aruch Hashulchan , YD 265:37; Chelkat Yaakov , OC 24; Kaf Hachaim , OC 170:71; Yafeh L’lev 265:21. Azamroh Lishmech issue 143