leathers melt on to skin???
most leathers i've worn have inside lining on them... and i dont think the friction of a crash is enough to melt leather onto you! now if you got doused with gas... then thats a different story.. youre just screwed... stop,drop, roll
injury from a crash imo depends on how you crash, speed, other hazards around you (other cars that will run over you, tree), and how you react to the crash!
If you are wearing the good kind of leather... it should prevent any abrasion in the event of a crash. You might end up with a broken bone... but it will minimize abrasion to your skin! I'm a nurse who has worked at ER & currently works at orthopedic unit so I see pretty much every m/c accident victims that come to our hospital! And believe me... there's a difference when it comes to injury between riders with protective gear vs rides wearing tanktop, short, and a flipflop!
as far as the guys youve seen crash and just get up! they were lucky! probbly jst lowsided... its less violent... as long as theres no hazards coming behind you ei a car!
also I think... this is just me... you can prevent more injury if you dont try to break the fall when youre crashing. Most injuries i've seen were broken arm, tibia, fibula, femur, ankle, foot, wrist, basically an extremity because they tried to break the fall. I think letting your self fall flat on your back or on your side, and just try to ride the crash out would decrease injury. But I understand that its instinct to break your own fall... plus I dont think I'll have time to think about falling on my back if I crash... I'll be just thinking OH SH!T
*KNOCK ON WOOD*