Unfortunately, this doesn't work if there's any possibility that the engineer has seen the patent (not terribly likely in itself) or been influenced by it indirectly (much more likely: maybe she's talked to a friend who read a web page on the subject, written by someone who had a friend at the company that produced the patent).
Once something is patented, the idea is out there for others to hear about (not just because they can read the patent; the original inventors can now talk about it, too). And ideas that get out into the wild tend to spread.
On the other hand, after all these years of having patents on obvious things granted, it might be no bad thing to try throwing out some genuinely inventive patents instead for a change :-).
(My own preference: either do away with software patents completely, or substantially shorten their term. [EDITED to add: the latter probably only makes sense if you can greatly reduce the latency between initial filing and granting. Which would be a good thing anyway, for all patents.])