It’s not about the gateway sending wrong information itself (or the owner making a mistake), it’s about someone using a script to set wrong location for other people’s gateway(s). Which has happened.
Yesterday I could not find the screenshots of that abuse (probably not posted in the forum but on Slack, no longer available). But it had the same effect as TTN Null Island, Atlantic Ocean - #4 by arjanvanb and Shenzen the new Null-Island? Dragino Owners please change the geolocation of your gateways! (Those examples are not related to non-authenticated UDP.)