It's common for parents to have a cute 'baby on board' sign at the back of the car window after they've had a little one. Many assume that this is either to signal to others that you might drive a bit more careful, and to encourage others to be more patient too. But apparently, this isn't the only reason why the 'baby on board' sign exists - and parents have been left horrified by the fact they didn't know. Taking to TikTok , user @pentagrammotorsport, a motorsport expert based in North East