If it is 'with risk' then it is not a sidechain. It s a multi-sig gateway. It should be called a multi-sig gateway. Calling it anything else is false advertising in my estimation.
As bitcrab noted.. some projects have claimed they are going to deliver blockchain interoperability in some way. There has been literally tens of millions of dollars of funding going into the research and development of this concept/idea. Still, nobody has done it.
Lets have a degree of realism about the technical possibilities with what is in reach with a virtual zero budget available to Bitshares dev.
Multi-sig gateways, sure, that can all be done right now. Just takes some individuals willing to take the risk and technical difficulties of running one. I for one won't participate in something like this till I have seen it working with considerable transactions. I don't want to be liable for the lose of peoples bitcoins for whatever reason.
So to recap. We are talking about multi-sig gateways here, not sidechains.
I'm not sure OP was talking about multi-sig gateways. He referenced Stan's graphic which I do believe was intended to relate to eventual actual sidechains. But I have no idea what Stan sees as the time frame. As for bitcrab's reference to "risk", I have no indication that he meant
counterparty risk. He could have meant that. Or, the way I read his comment, he could have meant the risk of things going horribly wrong. Kind of like what you cited.
Anyway, I do agree that sidechains are probably a ways off. If we want to be serious about them, we should probably be developing worker talent so we'll have more people capable of helping to implement it when the time comes.
In the meantime, I still like the idea of some kind of multi-sig gateway implementation. I'm sure there are risks. But everything has risks. Could multi-sig gateway have more risk than stealth, for example? I dunno probably maybe.