(Note that some experts have warned against babies sleeping in bouncy seats unsupervised, though I will admit to having let my middle child sleep in one out of desperation before I got a Rock «n Play.) (exclusivepumping.com)
In this case the expected risk of injury associated with bouncy castles was not a risk of serious harm, as in fact, tragically, arose.» (newlawjournal.co.uk)
The Boppy Noggin Nest Head Support (full review here) is another really popular product and works really well in bouncy seats and swings. (babyflathead.org)