I heard from a friend in Cambridge that thieves would often spend a few days in Cambridge just hoovering up students' unlocked bikes into a van, then drive over

I heard from a friend in Cambridge that thieves would often spend a few days in Cambridge just hoovering up students' unlocked bikes into a van, then drive over to Oxford and sell them for cheap. Then while in Oxford they'd spend a few days hoovering up students' unlocked bikes into a van, then drive over to Cambridge...