Those inspectors who are working in areas where the Uniform Plumbing Code is inforced should be seeing air gaps above the sink. While home inspectors are not code enforcers they should be aware of the requirements. In the 2000 UPC 807.4 requires an 'air gap' with the flood level markings at or above the floor level of the sink or drain board. That would preclude the use of a high loop.

My experience has been a high loop can allow a stopped up drain to back up into the dishwasher. I use to recommend installing an airgap or high loop but now I require an air gap as a health item.