If you can get hold of a long heavy steel chain, like the kind they use for lifting engine blocks from cars, just chaining a bunch of bikes together makes them almost impossible to move, because everything has to be carried together.
I know it's not a foolproof solution, but for some chancer who has managed to kick the door open but doesn't have bolt cutters, trying to carry/drag 3 bikes and a couple of frames all at the same time will see them getting aout 30yds before they give up. Especially if the bikes are pointing in opposite directions.
If you can get hold of a long heavy steel chain, like the kind they use for lifting engine blocks from cars, just chaining a bunch of bikes together makes them almost impossible to move, because everything has to be carried together.
I know it's not a foolproof solution, but for some chancer who has managed to kick the door open but doesn't have bolt cutters, trying to carry/drag 3 bikes and a couple of frames all at the same time will see them getting aout 30yds before they give up. Especially if the bikes are pointing in opposite directions.