This is true. If you violate a patent while knowing about the patent you are violating you can be on the hook for triple (treble in lawyer-speak) damages compared to a violation where you didn't know of the patent previously.

For this reason, a lot of companies I've worked for have had a blanket policy requesting that software developers never read patents, especially in areas the company is working in.

Of course the fact that you can very easily violate many patents without having ever read them is just more evidence that the patent system isn't currently serving a useful purpose for anyone but patent trolls and lawyers.