It will normally be the first spot that stays on Nigel. If a second spot a minute or so later includes an extra bit of useful information, then that might get preference. Previous to this action, the moderators were getting a lot of requests for it from chasers who found that the spots window was getting too cluttered with duplicate spots.
Obviously, it’s a judgement call as to whether a spot is an unnecessary duplicate or not, and then another one as to which one to delete. Sometimes it may not happen at all; there is no guarantee that at least one moderator is monitoring at any one time.
But as has been said, it shouldn’t matter whose spot gets deleted, so long as good information remains. A spot of my own got deleted by a fellow MT member this morning, but that doesn’t upset me. Far from it, I am grateful that someone is there giving of their time to maintain a good quality service to chasers while I am enjoying myself on a hill!