The rules were clearly stated and although it doesn't say, I'll assume it was a USATF certified official that made the call. Here's how it works: you typically only have USATF officials @ championship or prize money races sanctioned by USATF. They usually watch the lead runners from a vehicle. There usually aren't enough officials and/or vehicles to cover more than the lead runners. Thus, no, you can't have 'even' enforcement covering all runners. And, you can't rely on fellow runners to report infractions. Like it or not, uneven enforcement exists in this matter.
Some might say; if it can't be enforced across the board, it shouldn't be a rule. Okay, if there's no rule then aid can be offered to everbody anywhere by anybody. The potential for some to receive more aid than others is not a satisfactory situation. Level the field by stating aid is available at designated spots.
If somebody has a better way of dealing w/how and where to dispense on-course aid, speak up.