From what I've found out, it appears that payment recipients may need to ask the representatives to rule on every payment from untrusted sources. Further, it may be necessary to get a ruling on the entire transaction history tree of that payment! What if the funds were counterfeited ten transactions ago, and nobody in that payment chain challenged them?
You never need to do a ruling on previous blocks because the only time that you need to do a ruling is when there's a conflicting block/transaction and in that case you can't know which block to add to the blockchain. If a transaction is not conflicting with another block
then it is certainly a valid one because invalid transactions can be automatically detected by anyone, which is one of the miracle that RaiBlock brings. For example, a valid send transaction must have:
1) a signature encrypted with your private key
2) a valid previous block (thats the power of RaiBlocks Blockchain... when you build a transaction, YOU KNOW what is its previous block because only you can add block to your chain)
3) a valid amount base on previous transaction (and again, you know the maximum because you know what are the previous transaction)
Representatives task is very minimal, they are just there to make sure that everyone accept the same block when conflicting blocks are sent from the same wallet. Why is Bitcoin so complex... I don't know
In other words, the "Elected representatives" aren't getting paid. Thus, there's no incentive for anybody to keep a server online doing that job.
Well here's another miracle that RaiBlocks brings: Representatives get votes, decentralized votes with a weight base on how much money you have. Those votes are incredibly more valuable then lets say "facebook likes" and any IT businesses crave for more "facebook likes". Those businesses will jump on this opportunity, they will not only do the task well to get votes but they will do it well which will make the RaiBlocks network even faster. Not only it costs them nothing because they already have the infrastructure and there's no "proof of work" required, it will be a way for them to show that they can be trusted.