Ahh, the joy of submarine patents. For those of you not familiar with patent lingo, a "submarine patent" is one where the owner of the patent surfaces, seemingly from nowhere, at an inopportune moment.
Usually after you have completed the design and testing and are shipping millions of units. Like in this example -- the patent licensing company for Washington State University has just asserted a patent covering Bluetooth. Which is used, oh, pretty much everywhere these days.