Why is this privatised? Too easy to abuse.

If the ultimate goal, as it should be, is safety/deterrence, then a camera flash (reminds other motorists) is surely a decent idea?

I drove in the UK recently and there are speed camera warning signs everywhere, usually followed by quite obvious cameras.

Here in Australia, police have been known to hide around corners or position cameras disguised as roadside garbage bins, though I haven't heard much on this front for a while so maybe public outcry have pulled them a little into line. For the most part though, the cameras are not unreasonably located and an unspoken leeway of about 10% applies (e.g., can get away with 54 in a 50 zone).