I think some type of list of pond builders with satisfied customers would be helpful without calling out the bad ones. I once suggested a paid certification process with a test at the end. Things as simple as knowing what types of soil will seal, how to compact soil, core trench building, watershed sizing, etc. would weed out most dirt movers from pond builders. The course could have a cost, and a high complaint to compliment ratio might be grounds for removal from the list/certification (objective criteria and non-anonymous reviews). Its much easier to suggest a plan than to execute it though:)