As an aside, for those interested - my friends have a 'date' with a potential couple first and as far as I know, this is typical behaviour in the swinging world. They meet, they have a 'date' like dinner, or discussion over drinks and get to know one another, see if they're on the same page and looking for the same things.
IF they like eachother, and only IF...they proceed to discuss rules and boundaries if they were to progress.
My friends never sleep with another couple on the 'date' night, they've made a rule to 'date', go home and discuss and then proceed, if that's what they choose to do, together.
It's an art form, that's fo sho.