I agree with Val that it would be ideal to have officials have to tell when they are available, as opposed to when they are not. Ultimately, the current format creates more work for schedulers, since we assign games based on the availability list, and then end up reassigning them because officials deny games for times they have not bothered to set blocks for. There is no incentive for officials to set blocks, whereas there would be definite incentive to set availability: if they didn't, they wouldn't ever be available, and they would never get any games.