Possible but could be detected
Not "possible", it's a fact. I registered both of my main accounts and I know others have done tons. Detected? Doesn't matter, abusers will dump the funds onto Bittrex almost immediately. Even if they lost the smart contract funds, they still make out big.
You are correct!
You are absolutely right. To think that this behavior was completely unexpected by Byteball is a bit naive, really. As I wrote in a comment to the article, we just might have put quite a bit more thought behind this than people gives Byteball credit for.