-
they're also telling the criminals that they're going to get caught
Well, except they're not getting caught. Very few of them do. As Señor_Bear says, the cuts have cut deep. Also, they may be getting caught doing one thing, using one method, but if one thing doesn't work any longer, people just try different things and it all moves on. There simply isn't enough effort on prevention, and I'm not just talking about youth services being cut--they are in themselves something that addresses only symptoms, although they have a preventative effect.
I suspect the videos aren't just to reassure the public though, they're also telling the criminals that they're going to get caught.
I know someone who works with young offenders and one of the major issues is that they're making loads of money and think they won't get caught. If they're thinking it's more likely they'll get caught then they may think twice.