I don't worry about eating too much salt - I lose so much through sweating and exercise that I think I probably don't get enough if anything.

One of the big risks with hot weather and exercise is that if you sweat out salt, but only take on water your ion balance will alter twice as much, with potentially very serious consequences. It can be the case that drinking water can do mroe harm than good.

I don't think a bit of extra salt can do too much harm during a race as it will just be excreted if necessary.