That's the rub though. We aren't talking about deposits, we're talking about sending the bitcoin from the BT account to the people who placed withdrawals. Sending from their wallet, not receiving on their wallet.
The word "deposit" was just a single function I pulled out of a hat to signify business critical processes handled by a full node, but is by no means the only one. For a complete API reference, please,
refer here. It is not unreasonable, at all, to assume that their management tool (shadow scripts) relies completely on this API for any, and probably all, BTC related activity. Attempts to process cashouts, manually, outside of their management tool, though possible, in theory, would almost certainly have a negative impact on the integrity of the data stored in their management tool's DB.
Now, whether this is really what is happening, or just another excuse to buy them 5 more days of covering their tracks and milking a few more bucks out of duping more saps into "investing", remains to be seen. We'll know on Monday or Tuesday. I'm place my bets on HYIP/Ponzi (1% daily, really!?), but I like to think that $2 mil isn't enough to run off with and they are hoping to keep it going until they get to double digits.