I have never hunted in WoF or similar events but I do daily have to communicate with both my regular crew and customers and am very aware of lag issues or even chat failures in EU.
We therefore use out of game messaging (Webchat) and alternate comms (Mumble / TeamSpeak).
It is my understanding from chatting to socmates that are in WoF, that many teams have their own TS or mumble. Could there not be a set up for the match where captains, scorers and match officials are in one TS/mumble server, so that there can be no doubt and little or no lag when start/stop messages are issued. they can ofc be also typed both in mumble for timestamp and in game for duplication of in-game timestamp.
Another alternative that would not conflict with say the team TS usage would be a Skype message, though that does I believe sometimes have lag of it's own.
While it would be great to have a lag free game, and an end to issues like this, it is as likely as seeing purple snow or flying pigs. So rather than risk losing what is to many a fun and challenging event, think about how outside of game technology can resolve the problem, and keep it fair for everyone, as well as making the judges and officials life easier - it has to be a win/win.