I leave a cheapo Lidl lock attached to one of the many Sheffield stands in the car-park at work. I did it when I got the road bike, as I wasn't attaching a lock to the nice bike just for work: the car-park is secure, card-access and covered my constantly-monitored CCTV so unlikely to require a big, heavy lock. The lock really only prevents anyone knocking the bike over, or a joker moving it to another spot for a laugh.
Since I'm in at around 6.30am every Tues to Friday, I'm always first in so I'm not depriving anyone of their 'space' by leaving my lock there - that stand has been 'mine' for the last two-and-a-half years
But you're right, HlaB - it's sometimes not worth getting into petty arguments with tw@ts like the one at your work. Your solutions sounds like a good idea whilst you
** ahem ** dream up some amusing way of getting your own back on him !