The show is well-structured and the guests don't seem to be uncomfortable with his questions.. they all know the spirit he's asking such questions.
some do, but i recently watched one with shahzad roy and he seemed totally put off with BNA when she kept 'flirting' with him, at one point he even said kuch aur baat karien or something to that effect. if a guest is having fun with it, sure no harm, but no point in making them uncomfortable, sorta spoils it for the viewer as well. u know, be subtle, its more funny that way, instead of coming on like a ton of bricks.