Padlocks in parallel are two times less safer than a single padlock, because if one of them fails to open you will be stuck. Hence, this method is NOT recommended to shackle yourself to a stationary object.
On the other hand, you can use padlock connected in parallel between your hands and legs (hog-tie). If you leave keys in the opposite parts of your house, you will have to crawl to the first one, than to the second one to get free. But keep a saw or a file close at hand, just in case, especially if you are gooing to use many locks in parallel.

Also see Daisy chained padlocks