We have stayed in the Marina area near this Marriott many times (at the Westin) and there are signs everywhere telling you that crocodiles are in the area. In fact, it’s common to see them in the Mariana area around all the yachts. This area is known for having the biggest crocs in the area as they are fed just down the beach at the river mouth by a lady who sells raw chicken for the tourists. We have gone to see them (but we don’t fed them!) and they are absolutely huge!
On just the other side of the river, away from the Marriott, there are a number of beach bars and locals swim all the time DURING THE DAY. Every time we go to those, the staff reminds us about the crocs.
I feel really bad for the teen but this isn’t Marriotts fault.