If you simply put a sell order in for say 1.00 at your brokerage then as long as the price does not hit a dollar and trigger your order then you still have full control of your shares. $UBQU
I think they are referring to putting a sell order out where the pps is crazy high, to the point that nobody wiuld ever buy them. All these guys are saying that would in turn make them unavailable to Market Makers for shorting purposes. Since it is a sell order that you placed you can always cancel the order whenever. You aren't obligated to sell them or keel the order out either. Somebody correct me if I'm wrong bit that is the gist of it.
When people say lock up shares they usually mean to just put in a GTC sell order at a much higher price. Supposedly mm's can't borrow your shares if you do that.