After reading this blog post: https://blog.amigocloud.com/sub-meter-data-collection-with-an-iphone-into-openstreetmap/
I checked one of the created ways done after a survey with centimeter accuracy: http://www.openstreetmap.org/way/329799637
Unsurprisingly, all surveyed nodes have been imported in OSM. But OSM doesn’t need a node every 30 centimeters, even not every meter if the angle is null.
Someone to contact Ragi Burhum, AmigoCloud CEO, to explain that JOSM is also providing a “simplify way” function ?