Hi there, yes you are right and quite wrong all at the same time, being the commentator you mention sounding like telling porkies, i feel i should answer you,
yes zinc is deadly when heated, indeed anything galvanised should never be heated but this didn't stop them using them as grill plates, they were outdoors and after repeated use, the zinc etc will have off gassed the poisons so they were just grills, not something i would like to try, not porkies as you assume, just a hole in your knowledge of landrover history and it's anecdotal stories.
as for laps round the arena, there are pros and cons, more laps means less chat with drivers, in which case the crowds could have missed your "missus" talking to me about her converted machine, which i personally think would have been a missed opportunity to encourage others to do the same, and show her determination and courage....
sometimes the seemingly most simple things that go on in the arena are more complex than you can imagine . plus you cant please everybody, some like to talk some like to drive, some just don't show up at all, and we are left with an empty arena, which pleases no one!