It was a nice scene and I'm glad he was there to help but I don't think he would be considered an outsider. Bhavna is his sister in law (sali) and Rishi is his cousin. If memory serves that is why Yuvraj and family were at Bhavna's wedding because they are related to Bhavna's husband's family.
Plus I think he already was suspicious of him from the one episode I watched when he was at Suhani's parents house and he saw Rishi there. It looked like he suspected something but they never actually took that scene anywhere.
@pink- Absolutely! Yuvraj beating up Rishi was such a soul-calming scene to watch. 😡 he got what was coming. Just him being in the same scene would creep me out (Credit to the actor). I felt my entire body crawling.
@bold- Parm, I never understood why Yuvraj was the only one who picked up on Rishi's perversion. Why Bhavna's parents didn't understand it just beats me. He used to perve on Bhavna in front of them and they never got the signal. Even Suhani couldn't understand it, when she is shown to be quite good at reading people (only when it serves the storyline, of course).