If you do not wish to get warnings for some of the camera types, you can disable them on the filter screen.
You can always filter out specific cameras if you think that you are receiving a false alarm for them. When you think that you have a false alarm for a certain camera, tap the toolbar button on the main screen, and you won't get any more warnings on that camera. However, if you change you mind and wish to re-enable that camera you can do that from the personal database filter by deleting the filter for that specific camera.
The speed limit signs for the enabled cameras look like this: