How does OSM prevent trolling or vandalism? Since many (most) courier companies rely on OSM for their database a bad "joke" could prove very frustrating to many people.
This was not because of vandalism, but because of how hard it was to update OSM when you don't do it often and might not look trustworthy. In Danish cities we have a complicated relationship with cars, we don't want them, but we do want the people they bring. One of the obstacles we create is having a lot of one way streets, and when OSM gets an error on those... well... suddenly there is a lot of addresses you simply can't reach. I once updated one of these errors with a photo from the internet, and it was rejected after a few miniutes because I had used an image from the internet which is (was?) against the TOS. Unfortunately the company we bought the API from was not doing any form of validation, so we had a week where our 5000 employess couldn't registerer driving to the most commonly used adress in the neighbouring city. I posted all sorts of documentation proving my official function, and had a discussion with the admins and even though they agreed I was right they refused to let me correct the mistake without real evidence. So eventually I drove my bicycle the 50km to the location, took some pictures and a couple with silly hats and submitted them and got my correction.
Once we had a local copy of the danish map we had no issues. I assume you would do this for any app relying on working routing data.
It was in a place of the world that is unlikely to be popular within the OSM community.
The last time I saw a collection of "biggest objects" for various tags it was mostly things that were just subtly mistagged (e.g., an entire forest being tagged as a single tree) rather than vandalism.
If that forest's dominant tree happens to be a quaking aspen then technically speaking it might not have been mistagged.
The larger users of the data are doing some degree of validation of changes before showing them to users.