First off, thanks for keeping an eye out for misspellings and accidental new keys in the database. As someone who got one of your comments, I wanted take a moment to leave a note regarding “informing the original mapper politely”: perhaps there is something getting lost in translation so I’m not sure how polite “what is tag x for?!” sounds to German ears; it doesn’t strike me as particularly polite in English (especially the exclamation mark could be read as carrying some annoyance imo). Giving some context to users as to why you’re leaving a comment (especially new users) would be helpful, something along the lines is “tag x (in object y) came up as a new/unknown tag in the database”. At the end of the day, OSM’s free tagging scheme is one of the cornerstones of the project, so one wouldn’t expect a sort of Spanish- Inquisition for using a new tag ;-) Cheers.

Cool! One thing I noticed is that it doesn’t seem to be taking into account pedestrian areas, as can be seen here. These former runways at [Tempelhof Park](http://www.openstreetmap.org/#map=15/52.4731/13.4025] (Berlin) are used today as recreational surfaces and are mapped with a way along the centerline (highway=footway) and a closed way circumscribing the entire surface (highway=footway, area=yes). The GPS tracks are likely a bit farther from the centerline way than the tool’s threshold, so it suggests there may be a way there. In this case (and probably others elsewhere) it’d be good to check for pedestrian areas.