It's perfectly safe to read expired patents or patents that you otherwise have a right to. That's supposed to be why they exist, actually. The question is whether you've read expired patents to learn about the inventions in there or if you've ever actually used the knowledge in a patent your company has licensed (rather than just use it as a CYA).
I believe the OP's hypothesis is that software patents don't serve the patent system's primary purpose of disseminating useful knowledge, and he wants to test this.