Even a giant like Walmart backs down sometimes:
http://www.freakonomics.com/blog/2006/07/13/okay-to-steal-cheap-stuff-from-wal-mart/
And these are people who are actually commiting crimes. Enforcing patents is usually not worth it, and a tactic to drain money from other companies in the form of settlements. Little else comes from them (at least this sort of wish-wash patent)
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