I bought my gps unit for for navigation purposes, safety in school zones and to have access to the huge poi's available. To be alerted to redlight cameras and fixed speed cameras is a bonus for safety and not a tool to speed. The real speedsters are caught be the mobile units that cannot be detected by the gps units.
I didn't know it was forbidden to Germany/Austria to know locations of speed cameras. I went there last year and my GPS was very helpful to know their positions and the specific speed limit on the highway. BTW, be careful with mobile camera dingsbums !
It is not illegial here in South Africa to have speed cams loaded as poi database on your gps but the cops will arest you if you have any radar detection device like the locally sold cobra. Funny considering its not illegal in this contry for traffic cops to hide behind bushes and buildings in order to catch you.
The police is clever enough to check the GPS units. They are more or less good trained. There are actual open cases at court about that problem. Mobile phones with speed camera apps are illegal and you will get an penalty for the use.