The short answer is that it is simply a guess on anyone's part. So, at the end of the day, we simply don't know. All kinds of transactions can occur that are outside the typical realm of Level II B/A visuals. If two parties can agree with one another, for example, on an AON trade for that 700K block at 031 yesterday, then they both simply place the order and the odds of it executing as desired are virtually ensured. This is just one example.
I don't view these as buys/sells so much as I view them as a certain amount of money taking a position in EWSI at a certain price point. That 700K trade to me is simply about 22K dollars. Nice chunk to lay on an OTC stock.
This probably doesn't help much either, but at the end of the day, any and all trades are a private matter to those entering those transactions.