Although this rash vest discussion is extremely fascinating, I don't think players will really be loosing sleep over the fact the refs don't have matching uniforms.
The importance is to have good refs, what they will be wearing is secondary.
Of course they should agree upon colors of caps and shirts, but color of trousers, printed names etc, is in my opinion not a priority.
It is more important to set up teaching facilities to increase the numbers of good refs for the future. What better place to learn than the worlds. Even when just by looking from the side line.
If refs want to pay for a pretty vest with their name on it, no problem, but I wouldn't be spending too much time on organizing that part of the competition. Especially when there is still a lot of work on building the foundations of WAA.
Than again, different people different priorities.