No problem, it's probably one of the most common misunderstandings with access tags in the UK. Generally access tags should reflect the legal situation rather than whether it's safe or appropriate for a particular access mode.

Pedestrian routing software may prefer to use the separate sidewalks and tags like sidewalk:both=separate on the road should help with that. I think there are some cases where the implementation chooses to ignore separate sidewalks, in which case foot=no on the road might cause a problem.