Louveciennes is correct
They are designed to alert rescuers that there is a small child in the back seat. With a bad shunt, sprog seats can rotate forwards and are not immediately noticeable.

Or say there's a car in the river with just the back end above water level? Driver gets out but is unable to communicate that there is a sprog trapped within?

Happened last week as I recall...

The 'novelty' ones do get on my tits a bit, but I assume that anyone who hates these has no personalisation or adornment on their own vehicle? People make cars look stupid, whatever their breeding status.
(osok Rebel without a clue, Fri 2 May 2008, 9:19, Reply)