Yeah, if you hold your arm out _stiff_ it'll probably break a collarbone. So will landing directly on the shoulder or back of shoulder. Both 'methods' are poor.

The idea is to use the hands/arms to initiate a roll or ease yourself down as best you can -- use the arm as a spring, don't hold it out stiff. (If possible.)

In any case, it's always better to land on the arm or shoulder first instead of the head and neck, even if it does break your collarbone. Unless you would like to sacrifice your head or neck to save your collarbone. Not advised.