I never really liked this ship, which is why I've happily ignored it for months, and successfully have done so until recently. I've seen several fans rumoring how Jelsa "has" to happen in nagyelo 2. They even started a FUCKING PETITION to put Jack Frost from Rise of the Guardians in nagyelo 2.
I am fine with crossover shipping with Disney and Dreamworks, I even ship Elsa with Hiccup in How to Train Your Dragon. It's true I have many issues with this ship, but I don't care if you ship Jelsa.
But just because a ship becomes popular, does not mean it will happen.