"you've stolen this of mine," be it a physical object or a patent item, they usually tell you what the item you've taken looks like - they just don't walk up and scream you "you stole my thingie, pay me." Which is what Microsoft have been doing.

Mind you, to date they've lost four or five patent infringement law cases for each one they've won. So I wouldn't be too concerned if they accused me of a patent violation.