I think you've skipped a few posts. The suggestion was that the rightful owner takes it, in the repairmans absence, then calls the repairman to say they'll be round in a few minutes to collect it. Thus denies all knowledge of having taken it and likely prompting repairman to report it stolen to cover their back/try for an insurance claim (if it had been an unknown perpetrator taking it, who's to contradict him if he said it was secured at the time without blowing their own cover - he'd prevaricated enough on returning it before, why not claim to lock it up 'by accident' to do so again) whilst at the same time the owner is now in posession of a reported stolen bike.
The ins and outs of the repair saga are irellevant at this point, the owner has forced a false crime report to occur as some sort of revenge/joke and if particularly unlucky will be seen and arrested by cops who don't know the back story and won't be impressed when they find out it was all a hoax.
happily its all hypothetical tho.