Skate BMX helmets are a lot tougher than regular bike helmets. But I wouldn't go as far to say that they are made to take multiple impacts. If you have a serious crash, the foam is going to be damaged. The hard shell does however make it a very practical helmet, that can take many minor scrapes as well as being thrown into lockers and generally dealing with the rough and tumble life of a commuter.

If you get creative with padding, you can enhance the airflow in skate helmets a great deal. I used velcro dots to better secure the forehead foam pad which then let me cut an air channel in the center. Then I used 6 stick on foam pads about the size of a quarter to replace the top of head pad, which cut down on pad to head contact a great deal while still holding the helmet off enough to increase airflow.

Before anybody freaks, the soft foam pads secured with velcro are for comfort only. It is the crumpling of the hard polysyrene foam that absorbs any serious impact force. Try holding a bit of padding material over your forehead and banging your head into the corner of a door, then repeat with no pad. See. The soft pads don't do anthing except absorb sweat.