Under the Canadian Road Safety POI listing for Ontario, there are several Speed Camera downloads available:
Speed Cameras 30 km/h
Speed Cameras 40 km/h
Speed Cameras 50 km/h
Speed Cameras 60 km/h
Speed Cameras 80 km/h
Speed Cameras 90 km/h
Speed Cameras 100 km/h
and there is one, just called: Speed Cameras (without any speed limit number), and I think this one includes all of the above listed Speed Cameras (with numbers) locations.
If I will download all Speed Cameras, including the one without the speed limit number, then I think it will be duplication of each speedcamera location in the file.
At each location there will be one alert from Speed Camera (with a number attached) and another alert from Speed Camera (without the number).
The size of the Speed Camera file (without the number) is equal to the total size of all the other Speed Cameras files (with numbers).
I would like to know which one to download: the Speed Camera (without number), or all of the others (with speed limit numbers) ?
Per my experience, you should download them both and check them by yourself. Because you never know which one is complete, right? If you've found the duplications then delete them. For now, it's my way to correct it.