Thanks! The fact that this is the first time you've heard the word conveys a lot. We're looking at amending the tagline at this time. Would you know if there's a one word equivalent to footfalls? I don;t think footsteps would do it.
And those are the most common wordings in en-US: 'footsteps' is also the sound, and 'foot traffic' is the common term for the quantity of people walking by a storefront.