Ways not to lock your bike

Just scared off some lad who was trying to nick bikes outside Canonbury station. I think he was trying to nick a front wheel; saw him loitering as I went past, stopped, saw him duck down and I yelled "Hey". He looked up, saw me and rode off. I hung around for 10 minutes in case he came back. Which he will, no doubt, later. So if you leave a bike around there, lock both wheels.

I work just opposite the station and always see the same kid riding bikes way too big for him. And by bikes I mean 2 or 3 different bikes a week.

I guess he's still to find the perfect fit. Poor lad.