To explain why it should be illegal. Hey dude, what are you doing with that bike. Crook cuts lock just as the person attempting to stop them gets close. Now that person trying to uphold the law and protect someone's bike, gets the dose, retching and disorientated stumbles back onto the road and gets run over by a bus. Congratulations the crook that actually cut the lock, took off and received a minimal dose and you just killed someone.
If that is not bad enough for you, kids will be kids and the temptation to wear away at the lock so that it will fail just as you the owner try to unlock it, will be irresistible quite a few naughty children. Speaking of wear and tear, why is it, that you think it would be suitable to sell someone and wear and tear time bomb (you could imagine, bringing your bike in, greeting your family and accidentally dropping an old lock hard enough that the seal breaks and wow, will you family not be happy to see you).
Want to ride your bike to places and not have it stolen, start demanding bike lockers in addition to car parks. So open locker, hook up front wheel to raise the bike in a more compact vertical position, shut locker and insert $1 coin, set combination, timer starts, get back in time or locker opens and advertises bike for sale ;). You could squeeze quite a few lockers in two carparks. Counting numbers of customers, 2 inconvenienced to provide for 30 customers and not that expensive, say $250 a locker, last pretty much a life time, apart from the lock :(. What to accelerate installations, demand legislation to require bike lockers at all retail locations (number of bike lockers required per number of car parks, for planning requirements those lockers spaces should still count as car parks, car parks are really expensive to put in, far and away more expensive than most people think). The do really need to be vertical though, so push front wheel onto hook and rotate large counter weighted lever, to raise and rotate bike into vertical position.