Cast members ARE allowed to describe how they look.
Vanessa explained in an interview with People Now how some couples got around not knowing what the other one looked like: “I asked the girls, ‘What’d you tell them?’ And she’s like, ‘Well I said I look like this celebrity,’ and I’m like ‘Oh, I can see that,’ and I go, ‘What did he say?’ And mind you, I’ve seen all the men. And she’s like, ‘Well he said he looks like this celebrity.’ And I was like, ‘Okayyy.'” Awkward.