As per Sonakshi's Instagram she is coming to BB for Dabangg promotions and Salman will do nothing to ruin his movie promotions.
Now let's assume that this Arhaan child rumor is true. Then going by the promo it will alter the mood of the house too much and will be such a big scandal that Dabangg will get sidelined. I'm sure Salman would never let that happen.
So even if Arhaan does have a child?( he most likely doesn't), Salman would never choose to address it at such a time.
This Arhaan's child thing is surely a prank by Salman as he would want to maintain good vibes in BB especially today.
Also this stupid prank will take the focus off of Sid's violence again.
Though if it's a prank it's a terrible one tbh.