That is an option that can be changed, there have been indiegogo projects such as the ubuntu phone, that would only have charged if funding had been successful.
Not true. I was frustrated when indiegogo deducted money from my bank account instantly when I pledged for the Ubuntu phone. It was surprising because I had only pledged significant amounts on kickstarter previously. Honestly, for someone without much in the way of liquid assets it was frustrating to have so much money frozen for over 30 days.
And you highlight probably the biggest issue with indiegogo's approach. Keeping money tied up while waiting for the project is pretty bad.