How do you lock your bikes on this rack? I wouldn't trust leaving my bike unlocked in a place that others can easily access. I'm always hearing about someones bike being stolen from a "storage room".

Also, I'm sure the public vertical racks must be different than this and offer locking. I hope anyway? Just curious what that looks like? Is theft prevention sacrificed for space convenience? How could it be more secure than thick tube racks anchored in cement?