I'm building a platform for to-be-married couples to connect with travelers who want to attend their weddings for a deeper cultural experience: JoinMyWedding.com
You need to build trust in your vetting process, which means you actually need a good vetting process. Some ideas would be to have reviews of the potential guest from their facebook friends. Each review would have links to the reviewer's facebook profiles. Have links to the potential guest's own facebook profile, twitter, linkedin, etc. The more background links you provide, the easier it will be for the wedding couple to decide whether to invite the person or not.
I don't know if you will ever get to the point of convincing a couple to invite a stranger to their wedding, but those things will at least get you closer to that possibility.
If you'd like to brainstorm other ideas on the topic, let me know,
I love this idea! Lead with a story, focus on creating an idealistic story line that couples can relate to... feel exited about and justify to themselves having a stranger in their wedding. Make the focus of your website's and marketing pitch... stick to it, don't settle or try justifying yourself to the potential market - make it seem as if there is already an existing demand and solution by always having a story of how amazing it is to start a new with new friends, cultural growth and opportunities for friends around the world.
This is a two sided market place but you need to have weddings first.. once your content is there, lead with a story to travelers and target them through their appropriate social networks. it will be a lot easier to get people to join a wedding than it is for those getting married to invite strangers. - make them non-strangers first. always lead with a story, for yourself, for the joining and the to be wed - to learn about each other and the context in which they will meet.
I don't understand the last bit of your question "so reviews can't be used", so I'll answer the first bit about building trust.
For the to-be-married couples, trusting who will come to their wedding is really important because of the potential risk associated with having their event ruined by "bad guests".
Building trust = reducing that risk.
How? Couple ideas:
1. Require the guests to link their social media presence. It's functions like a background check. One filter that could be useful here is to only allow linking to accounts that are at least a year old (or whatever period you choose )
2. Video interviews could be a good way to build the rapport also
Beyond the trust building, you can also reduce the risk by doing things like the following:
1. Have the guests join only part of the festivity that are less risky (bachelor's party) but still part of the culture
2. Have them seated in an area that can be controlled
3. Make explicitly clear that if the guests do any disruptive behavior, they'll be removed from the event
4. Have a representative of your company be present at the wedding or stand-by in case problem arises
Hope this helps.
Ahh - an interesting problem. You could outsource "reputation" to their other social media presence - for instance preview their facebook or instagram profile to see if there is a connection. I wonder if this is even better than reviews actually - especially in such a personal context as attending a wedding. People likely want to look for "someone like me".
I think about trust and reputation a lot as I work at a 2-sided marketplace company. Happy to brainstorm ideas with you :)