If the wind shift is significant enough to warrant a mid-race change, you should have already noticed it well before you got to the gate.

Even with World Championship-level RCs, we need to identify the shift, determine if it will stay, and get the change equipment and teams in place to make the change (obviously, some of this should be simultaneous). Meanwhile, the sailors have been sailing in this new wind. By the time the change is signalled, it's old news to the sailors (ie, the downwind leg is a reach because of the shift).

Also, it only matters if you're the first boat or two at the gate. If you are, you're good enough to have picked this up. If not, you're following the leaders anyway, so just follow them to the new mark.

Mike