This feels counter-intuitive to me. I understand why patents are tainted by these, but how am I supposed to know if I'm not infringing if I don't research the idea before shipping out? Shouldn't there be a way to make sure at least it's sufficiently different to make sure I'm not repeating something?
Your lawyer or a consultant does a technology audit. I used to do these on behalf of VCS on young startups to ensure they had not infringed on a patent that would put the investment at risk.
At the time it was hard. There wasn't Google Patent search which is really useful for checking these things.
Basically I would look at what patents the fledgling startup had filed. Make sure they didn't suck, and that there wasn't lots of prior art.
You can be a start up and get bought for nothing more than a single patent that someone wants, so making sure the patents you have are not going to fall down when a bigger company wants them was important.
Often I would also be checking who beat the company to what ever they were doing, and then check those people's patent portfolio.
We didn't worry much about things like the Fat32 patent, we worried about things like hey, this isn't a real innovation these guys just read this other guys thesis paper and knocked it off. (Like Nick at Summly did)
From there a VC could decide if they were going to double down or cut their losses.
So basically a lot of NDAs ;) We're going to be doing feature lists for our last project before going to marketing, so I guess this is as good a time as any to make sure the lawyer combs though them.