It is economically naive to fail to consider that a feature that adds value in one economic condition, may subtract it in another, and that movement of money may follow this with a lag, sometimes a very significant lag due to practical constraints.
Further naivete would be in imaging that this is not happening all the time, and that this effect is commonly exploited. "Economists" here are contemplating only static ideal cases, and implementing regulatory changes in spite of these concerns. Changing the code is changing what ultimately regulates Bitcoin.
With this particular change, it is not so easy to undo it if it turns out to be a mistake. Many Bitcoin may be destroyed. People will make mistakes of trust.
There are many new risks with SC. Lets address them rather than pretend that they don't exist.
You make many sensible comments and let me insist I am not trying to downplay the potential risks of sidechains.
My problem is that most of sidechains opponents in this thread are justifying their risk-case with a proposition that involves the creation of coins booted on sidechains.
To my knowledge, coins booted on sidechains are the economic equivalent of altcoins and in no way are sidecoins advantaged over altcoins. So in essence, sidecoins are not responsible for that problem and it is misguided to suggest that they are.