When there is a large gap in the margins someone will buy or sell 1-10 shares seeing if people will bite, and they have big time today. This would be illegal on a regulated market and honestly shouldn't show a change unless its a larger percent of the daily volume.
metals, forex and commodities are all regulated markets and this kind of trading goes on all the time. It's what high freq traders do looking to sense price direction - both publicly and on dark pools.
Precious Metals are insanely manipulated, just look at the squeeze on Gold/Silver on over the past 2 months... it's blatant.
That being said, our entire US market is massively manipulated.
If you think the SEC is watchdogging and regulating to any decent effect, you're giving them way too much credit. They're under the thumb of the powers that be.
