Well i'll give you 20 out of 10 for creative

About the only application i can see for piggybacking is for injured or charaters in coma.
As for fall damage whethere you fall, jump or are dragged off a cliff your gonna get real messed up if not dead. no amount of " but he hit the ground first is gonna help ".
Lastly how would for argument sake a 4ft Dwarf give a 7ft Kran a piggyback even if he/she was strong enough.
Ok thats enough of me killing the idea so how about i breath a little life into it.......
Working on your basic idea of weight if you add in the effect of a counter lever which i'm sure you all know allows for a person to lift multiply times their normal strenght would allow, how about hand pulled carts.
Bah just an idea that i'm sure has come up ( to be honest haven't checked other threads yet

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