I've been a bit torn with this, I first saw it as advertising content, but then later realised that when looking about a carpark, especially in low light, you don't tend to "see" cars with tinted windows specifically, you tend to see odd stuff, things sticking up, highly coloured things. Black (or highly tinted) windows sort of blend into the background. ~Add to that the fact that, as said above, its a damn sight harder to get through a tinted window so takes more time, I think it provides an overall deterrent, but at the end of the day I have had my windows smashed and my boot searched in an empty car, as have members of my family – it seems they either do it pro-actively to find stuff, or see stuff and react. It's swings and roundabouts, but I think there's overall added security rather than reduced, as it removes that immediately visible bright green bike that catches the eye in a carpark full of other more expensive cars when you've stopped for a bite to eat. That said I still lock my bikes into my car, but I will probably be tinting my estate when I get chance, it does look better regardless of what it's associated with, I don't do things for what other people think.