Curious Cab driver

Ok, I’ve been reading a lot of post about swingers and cuckold partners, I’m a cab driver in the Caribbean I also do a lot of private rides, to and from the airport but I’m also curious to know, how would you know if your customer a swinger or cuckold? I’m new to it all and would like to experience it for myself 🤷🏽‍♂️ is there certain signs I should place in my vehicle for verification??