There has been a few historical initiatives to prevent politicians (and their families) from inside trading, including projects that exist to track and record it. Most seems to focus on congress. I also recall attempts to outlaw politicians from playing the stock market because of the obvious risk of inside trading, but I don't remember any success in that area.

Looking at tracking data, it seems that a few individuals are responsible for the majority of trades, but there is also a fairly long tail, and they don't track family members who could act as proxies.