Bad for the sport argument also holds for Derby starts on Friday. Amateurs who want to try field trials are likely going to want to start at the first rung of the ladder (derby).
There are four derbies in a row over the next 5 weeks in my area and all 4 start on Friday. Luckily for me, I own my own business and can manage to get away, but I'll have to leave on Thursday to travel the 5 hours to get to each event. That's work all day Thursday, then drive 5 to 7 hours, then get up early for Friday derby start. How many people are in the unique position to handle that schedule just to get involved in the sport of Field Trials?
It is definitely a limiting factor. But by the way the judges talk about large entries and needing more days to judge the stakes fairly, maybe no one cares if Friday starts are a limiting factor... Obvioulsy there are lots of entries for Am and Open already.