Look, I know that none of us owns the bike rack we have, for the sake of convenience, left our best lock on: I myself have sometimes put my bike on a rack with someone else's lock on it when the one I usually use is occupied.
But you have been locking yours in the space next to mine for a good six months, right through the summer when the bike shed was snided. So why, suddenly, have you started to use the rack I normally use, where my lock hangs, despite the fact that (because it's gone a bit cold the bikes have thinned out) the parking pickings are now better, and the space you've been using happily for the last 6 months is completely free?
If the plan was to mess with my head then you've succeeded.