For us this would depend largely on our relationship with the other guy. Is he just a guy we've played with a few times or is he a "boyfriend" for her. Most of the time we play Stag/Vixen...I am there or even participating in the play session. There have been a few times with men that we know and we trust that she has played alone when I am not available (work, out of town, etc.). Our rules for those sessions are simple...ask permission, treat her like I am standing right there and take photos/videos. Media must be shared with me during or shortly after the session. I think that traveling for a weekend away would have the same rules attached. I will say that the idea of someone traveling to us for sex is odd to my wife. We have had several men offer this and we have turned it down.