Scheduling Question

[JefferMC]

This weekend I was at my U10 daughter's recreational soccer opening weekend, where all the recreational teams play a 3 game round robbin for placement into divisions for the season. IMHO, this is a fairly large organization. The complex had the 4 full size fields divided into a total of around 16 smaller fields and were constantly running games on them from 8 AM until late afternoon on Saturday (and shorter hours Friday and Sunday). Now that I've set the stage, this is the question:

The single (I'm guessing 16 year old) ref for my daughter's first game (which started at about 11:15) was obviously beat before they took the field. He lay at mid field during half-time. A parent sent him a bottle of water.

I spoke to him after the game and he said he was scheduled for 7 straight games, and this was good because those working the afternoon shift got 8 in a row. The high temperature reached 97 that afternoon and had to be above 85 by game time.

What would be acceptable standards for "professional" referees in this sort of environment? Two games on, one off? Alternating?

I'm sure that they have problems getting so many referees, but what they're doing seems reckless.