Zoombezi Bay (should I?)?

Who has been to Zoombezi Bay? Cause I'm going there for my b-day and I am starting to get a little scared cause of how big and long the slides are over there. Any tips about how to be safe there.... cause I heard a family got severly hurt there. Also do you have to do any thing or become a member or ANYTHING at all. Cause I heard something about signing up or something to be able to go in the pool. Tell me anything you know about that place please.