I had this in a reply but decided to turn into a post. We are looking for a long term FWB and frustrated by the flakes and fakes, here is a PoV on deciding factors and process while vetting. Curious to see where folks land with their experience.

 Here are the risk factors that we look for / process.

• Proximity - if it take more than one hour to get to us, the risk of flaking rises exponentially.
• Fly in Fly out - Similar to above. You have to work around their schedule, and it is really easy for them to bail, (and they are likely cheating on their wives)
• Profile - low word and pic count = low effort - If they can't be arsed to have a good profile, how reliable will they be?
• Pictures - Some racy pics are fine, but lots of dick/sex pics and obscure, non-representative face photos are a no and means they are clueless or hiding something.
• Communication Cadance - Are they responsive to a chat, or is it like texting someone on Uranus and waiting for the signal to traverse the solar system.
• Communication style = Do they speak like a normal person or is it like talking to a toddler?
• Can they host? Not definitive, but could be a sign of cheating. Again, aside from risks of being involved in a tricky situation, it means that the risk of flaking due to guilty conscious is high and at best, you have to work around their ability to dodge their wives.
• Did they actually read your profile? Put an easter egg in to see if they have taken the time to understand what you are looking for.
• Meet straight away after contact and no play on first meet, meet us both separate: As we are after a longer term FWB, we get them to meet her, then if she likes me for a second opinion. It elongates the process and the ones who are serious are willing to do this, the others bail before meeting husband. We make the meeting logistics easy as possible.
• STD test up front - No papers, no play and we reciprocate. Again, sorts the men from the boys.