Stolen bikes

And in a place like Oxford, where a significant amount of people don't even lock their bike to anything, you'll be reet. Two Kryptos and your bike will never be the easy option.

This. At my old house we had a couple of nice-ish bikes leaned against the wall in the front garden unlocked and for all to see and they never moved. In general the bikes that get thieved in Oxford are either unlocked shoppers, or nice road bikes locked with shoe laces. Two kryptos means no-one will even look twice.