No, will not get confiscated.
Edit - apparently they can based off the replies - we have brought them on 3x and never had them taken!
Note - they don't work very well on board. We brought two different models and both only worked INSIDE the cabin or very close by. We planned on putting our infant twins to sleep in the loft suite, then eating dinner a short distance away at coastal kitchen. But, monitor did not reach so we just had to hire the baby sitters on board.
Also, WIFI monitors WILL NOT work on the ships network.