Should a child's pfd fit loosely?

No, a child's personal flotation device (PFD) should not fit loosely. It should be snug enough to stay in place while the child is in the water, without being restrictive. A properly fitting PFD should allow for some movement but should not be able to slide off over the child's head. Always ensure that the PFD is appropriate for the child's weight and size, according to the manufacturer's guidelines.