2) These type of attacks can be addressed by having a non refundable cost associated with moving coins into the side chain or out of the side chain.
The attacker can recover the cost with the proceeds of the attack. Eventually you have to raise penalties and fees so much that the side-chain isn't competitive with an altcoin which performs the same features.
I would be careful with statements such as "Side-chains are simply a broken concept." In any event, I have introduced demurrage into this argument and if anyone gets the idea to patent this here is the prior art.
I am confident with that statement. The security of the main chain is reduced to that of the side-chains because chain reorganizations on the side-chain put them out-of-sync causing all the coins in the side-chain to be in some limbo which can crater the market price of all the coins on the main chain also.
The security problems are related to the issues I pointed out for the Cosmos project in that there can only be one synchronization order (not multiple relative ones):
https://github.com/cosmos/cosmos/issues/47I already proved the security of their blockchain hub concept is broken and can't be fixed. They banned me from their Github because of this.
No amount of BS from them can change this fact.
Note if I wasn't so
cognitively limited for the time being, I would probably have pulled it together by now in irrefutable elucidation, but this is the best I can do for the moment.