I would definitely (and will now) look into it. There is nothing more heart breaking and disappointing then coding for hours, setting up an infrastructure, becoming bootstrapped...then getting a cease and desist. Only thing to compare to that type of disappointment would be doing a quick patent search on a business method you might be implementing.
There are two issues with what you suggest (looking up patents ahead of time):
1. Many times the Cease & Desists, or "Invitations to License" are about completely tangential topics or technologies to the core of your business.
2. If you do specifically look for patents ahead of time, and this becomes known in any legal proceedings, the penalties for willful violation of assorted IP are higher. IANAL but have heard this often enough from people, without seeing it refuted. Someone do correct me if I'm wrong.
