If internal control was that weak, it's not just about submitting a bunch of invoices for payment and they get paid without question. These kinds of projects usually have quality checks and signoff before payments happen. So lets say if I were heading up finance and co-responsible for development, I would get an invoice, review scope, confirm items actually done (personal site inspection, hard hat and all), look at inspection report from owners' engineers, match to site inspection to the extent possible, say ok to pay with my signature. So I'm thinking the internal control issues infiltrated the build quality  as well. Of course, sometimes public employees don't want to sign off because they like their jobs without recourse in political reviews. Recall Hanabusa grilling people that should have known, etc, and everyone in a position to have done something were unhelpful. Signoffs have their drawbacks, but that's why we should have them. These are people getting paid for it.