It is easy to spot when penny stocks are shorted - especially when you have bids in depth and the shorted price is set below it and you are lucky enough to be given the shares at that cheaper price.
Also, it was obvious when shorts were trying very hard to hold it back during the short squeeze to .0196 with multiple trades up to 50 ticks lower going off every 5 minutes or so.
I explained that in detail in a contemporaneous Trading Summary on the more serious trading forums.
Anyone know/heard of ANYONE who's ever shorted SUB-penny stocks?
Yes, Tim Sykes, Michael Goode, and some others. It isn't all that popular a strategy, because it's hard to get borrows and the associated costs are high. The possible risk is even higher, since any penny stock, however slimy, can run big at any time.
SUB-penny?
Nooo. Not subpenny. They usually choose bad stocks that are over a dollar. Or are at least 75 cents or so. And even in cases like those, it can be problematic.
Ultimately, you can believe what you want, of course and I'm not going to debate it. But to me, the "MMs shorting" is mostly used as a scapegoat when a ticker isn't doing well.