I also like the idea of not dividing the skill levels, though leaving the door open for some to be limited to advanced tiers for traditional salmon flies etc. How it gets regulated might be tough, perhaps the people signing up just vouch for themselves?
Though it might be tough to regulate containers, it doesn't seem unrealistic to ask folks to purchase this type of box
. It's cheap, available from many different places, and are also useful. If flies are sent back in the same container then it can just be reused.
I like the firm deadline idea, removes questions and waiting, etc.