RE:RE:Manipulation or the sector is in a downward trend.Unless one is positioned correctly and has a boat load of cash one can not take full advantage of major corrections.
IIROC is a regulatory authority and may have many limitations but they do monitor stocks. They have experts looking into any unusual activity and will investigate. They have monitoring programs that will flag activity and transactions. If someone with little knowledge of markets can see manipulation don't you think they will not be able to see that when it is their full-time job to monitor stocks and they have the experience, equipment and software to do it. Clearly, they are understaffed and can miss a lot too.
Do you know that before open if you put in an order at the very last second that changes the opening price you will get a call from your broker who will investigate if you made a deliberate attempt to change the opening price? There are systems in place that generate certain flags that get investigated.
There are situations that are in grey areas. high-frequency traders can be constantly shorting and then buying back in the day. It is the net position at the end of the day or the reporting that counts. As long the HFT are complying with the laws they cannot do anything.