I think a decent strategy for a tall person, say, would be to accede to requests for help if the request doesn't require you to go significantly out of your way or put you at risk of significant harm. The same strategy would work for the strong person and the smart person. But it most emphatically would not be good advice for how a woman should deal with sexual propositions.

But having sex with unattractive people does usually “require you to go significantly out of your way or put you at risk of significant harm”, so you don't need a special case for that.

It's a continuum: the fraction of times it's reasonable to pick stuff off shelves for people as a favour is close to 1, the fraction of times it's reasonable to write Web pages for people as a favour is close to 0.5, and the fraction of times it's reasonable to have sex with for people as a favour is close to 0.

(And anyway, if I understand correctly what type of people OW is talking about, they feel obligated to reach stuff for shorter people even when they need to go out of their way or risk harm to do so.)