Hands-Only CPR?

I just saw an ad for Hands-Only CPR.  I clicked on it (a web ad that I actually clicked -- that virtually never happens) and it turned out to be a broken link, but I then searched for it and found the site.

It says the following:

It’s not normal to see an adult suddenly collapse, but if you do, call 911 and push hard and fast in the center of the chest.  Don’t be afraid.  Your actions can only help.

But can that really be true?  Surely it’d be worth having some broken ribs if it saves your life, but... it seems unlikely that in 100% of these cases "your actions can only help."  Is it just me?