These are essentially artefacts of our centre line modelling of ways which in general can be handled if width tags are present (and even more easily if dropped kerbs, tactile paving etc are mapped). Other equivalents are streams going into a lake which is part of a river: Does one connect them to the river centre line or the outline of the lake? In some GIS data, e.g., NHD, these have an additional attribute of artificial_path, i.e., they are logically necessary for the network model of the system but should not be included in other representations, such as rendered maps.
For single steps widely spaced on a path i have just mapped the step as a node & highway=steps with step_count=1. I’ve been less sure about what to do when the steps are roughly 1-2 metres apart.