I have a pair of bolt cutters that will sever a link in a 1/2 inch chain in one swipe. About 5-10 seconds to place the cutter around the chain and another 2-5 to snap it. As a matter of fact I recently lost a key to a very large pro grade master lock and was so impressed at how handily my cutters snapped the lock. Made me realize once again how easy it is to break a lock and steal anything.

But in the visible area you describe I doubt it would happen. It would be so obvoius what is going on.

There are sevral places around here that I am ok with locking the bike up. But they are also very visible and publicly frequented.