With BitPools you vote with your bitcoins. If someone creates a proposal and someone else creates millions of bitcoin addresses and fills each address with the minimum vote amount (ie. 10 mBTC) and sends their bitcoins...what would they gain?
It is built to scale quite a bit.
These two people could be colluding like how politicians and companies collude to have certain contracts handed to a specific company...
Also someone who creates a proposal could then vote for themselves, surely that invalidates the integrity of the system?
Since the vote amounts are being refunded, it doesn't cost anything to rig a vote.
A fully fleshed out example:
Problem is proposed
People make pledges
Person A bribes Person B to propose a solution that will use Person A's business/company/services
Person B proposes solution
Person A wants Person B's solution to win so makes a lot of fake votes thus crushing the other solutions
Vote fees are returned and Person A witnesses improved business at little to no cost
Some people cry foul play but because the votes are anonymous you can't deny the results because there would be no explicit evidence.
If I have correctly understood the system you have produced then this method will work 100% of the time.
What you have made is something necessary in the world but I don't think its in the best form.