Hi.
For us, attending a party always comes down to the following...
i) Whom is hosting obviously. Would be be interested in them ourselves?
ii) If they are giving a vibe of "collecting" attendees ie; trolling just to acquire a selection of play partners, that's a huge red-flag for us. We're not interested in being ticked off of a "list" of people they are interested in, then to be discarded because they realize we're not DTF or providing what they want. Unfortunately we have attended gatherings that felt subtly manipulative in that way. If it feels less like an altruistic endeavor & more of a "trolling" experience for them. Hosts should NEVER create events for their own indulgence.
iii) We don't expect to know who the attendees are, but it's nice to have a general idea. Nothing worse than being at an event and realizing one of the attendees is not in a good place with us. that's awkward. So going in "blind" is a turn-off. Many people have others on their "block list" here, who wants to be in a room with people you have blocked. So for us knowing who the other attendees are is helpful.
iv) A host should always make it clear what the expectations & rules are. If it's a designated "Full swap" play party & it's presented as "What happens is up to you", this is disingenuous. False advertising becomes predatory in that sense. Call it for what it is and make it clear that anything else is off limits.
v) Partly related to the above... attending a party where everyone has established play with one another and/or a sexual history together... but you're the "newbie" or "fresh meat". Yes, we want to explore with people sexually, but NOT become part of a "collective".
vi) Gossip. We like an exchange via chat or email with a host before attending. During that chat there are certain things we look for in the way they talk with us, Gossip being a huge red flag. We were invited to an event and during a chat they started bragging about whom they had hooked-up with. Not cool. Private in person conversations about certain experiences will happen, but online gossip is not a good thing.
Maybe these things are more specific than you're question asked, but they stand out to us.
We are interested in gatherings, even leading to private parties. We are NEVER DTF at any first meeting. You want us? get to know us, like you would with dating someone. if we want you it's because we've gotten to know you... and we like you. Doors open up after that and it's far more satisfying being with someone you enjoy the company of non-sexually than just enjoying a piece of ass - so to speak.