For example, at the time that iD migrated away from the crossing=zebra preset, the area around Cincinnati had more than 7,500 crossing=zebra nodes and ways, about 1% of all crossing=zebra occurrences globally. This is a part of the U.S. where the longitudinal bar pattern remains relatively rare, where “zebra” crossings don’t exist as a formal concept in the real world. Since then, more than 2,000 crossings have been retagged with crossing:markings=*. But in the same time, only 250 new crossings have been positively identified as crossing:markings=zebra, including crossings that were never tagged as crossing=zebra to begin with. Some of the 1,100 crossing:markings=yes occurrences may in fact be marked with longitudinal bars, but this still indicates that a very significant share of crossing=zebra in this region, probably a majority, don’t have that marking pattern.
(Hopefullly I got these queries right; I find it quite difficult to track tag changes over time with the Overpass API.)
As the infobox for crossing=zebra notes, a more reliable replacement would be crossing:markings=yes. This isn’t as specific as crossing:markings=zebra, but it will avoid diluting the meaning of that tag. Similarly, iD has been suggesting crossing:markings=yes whenever it encounters crossing=marked.