Hi Quickstep
No, you won't be falling forward - just moving forward.
If we take the transition from step 1 to step 2 in the waltz natural turn. I'm driving with my standing (right) foot. My hips are forward under my body and my right shin is angled forward. My standing ball of foot is a little behind my centre of mass (i.e. my body) but it doesn't matter - i'm not falling forward, i'm driving forward and my left leg is just about to swing through for step 2.
I think Anonymous is about right on this.(though i don't agree on the "the weight is on the foot" thing, but i'm sure we both mean the same thing).
In fact, i'm trying to improve my dancing by improving this very action. Up till now, i've tended to stick my bum out a bit which leaves my hips and body a little behind (hey- that's a good pun!!) where they should be and is impeding my body flight.
I don't think of "body in front of foot", i think of "let's get this body driving forward with good shape"
I haven't tried this dance movement in a shopping centre because i'm afraid all the ladies will mob me to dance with them!!