Not necessarily.

The existence of the "dark pool" was well known. Anybody who read Ron/Shamir paper and choose not to ignore it (or actually had attention span to read it and ability to understand it) knew that is very probable.

It doesn't even take that much analysis: everybody who has been following BTC closely knew that there are 'entities' out here with a huge stash of coins, min 500,000 that they got for pennies.

Ron/Shamir also documented some curious patterns. For example a pattern where a single address would sell hundred of thousands of BTCs to multiple destinations, and, through Mt.Gox, they would all return back to the same address.

I called that market-making in one post. You can say it was testing and preparation for today.

That is really nothing unusual for stocks and is often very easily visible on pumped-dumped poorly liquid penny stocks.