It's also good to look on company background. If they worked for a long time on project, before making ICO, it's a good sign.
You have a good point but if you focus on the company or developers background you'll never know if they're telling the truth because everything on the internet isn't real and can be copied or can be fake.
In my personal opinion I usually check their social networks like telegram because good bounty campaign ICOs have good social community.