You weld the top (chains) and the sleeve at the bottom. There is no way to get the basket past these points so you don´t have to worry about welding that to the pole.
This will not interfere with moving baskets. It only makes the lock actually worth puting on.
Technically, they could still be taken, but nowhere near as easy as it is now.
If it kills, I got news, it ain't a side effect