You could be right.fine in principle.., but not in practice...
getting outside routing assistance means planning to cheat - most people won't do that.
but.., clicking on a website.., that's just too easy and too tempting for some.., the tracking data is so valuable that the temptation will be very strong
in any case, even if everyone _did_ manage to resist the temptation.., there would still be a widespread belief that some people did look at it - "how did they know to change course and go over there?.., there is only one way they could have known.."
there would be so much questioning of the compliance with that rule, that it would be poisonous.
Maybe something like 2 hour delay until Friday midnight or maybe Saturday 0600, and then switch to real time? By that time the really fast boats should be finished, and everyone else fairly well committed - if someone made a major change of plan based on tracking there would be a price to pay.
Even with delay, post-race analysis would be really fascinating.