After having done testing and debugging for various Open Source software programs since ~1983, without making too much rambling and bragging about it, a incident forced me to stand up and fight openly: I was sued for analyzing a GPL-licensed VoIP-system my company had intenton of selling.
I am the technical manager (and partner) of a new Norwegian company within the IT and VoIP market. Our supplier could never get the product working - so I analyzed it and found what was wrong. When the supplier found that I had analyzed it, hell broke loose...