[AquaDome]

If you're carrying that kit around, you certainly aren't weak.

[Canada_Rockies]

Theoretically, you only need one. If its a metal tripod and its cold, you only need one grip to carry it. If you're carrying it on your shoulder, you only need one leg padded. Theoretically
Although in my view, I'd want all three legs to be padded! I don't see that it would be much more expensive, or much more bulky/heavy.

So, to answer your question - who knows?

I know! Use pipe insulation and black electricians' tape on the legs. Down right cheap in all senses of the word, but it works.