Casual language, where the user "violates" the terms of the warranty, then Apple "voids" the agreement. The user wants to breach the terms, but would still like the cover provided by the warranty. They don't set out to void the warranty as a goal, if Apple were to uphold their end, the user would be perfectly happy to keep it. So, the cause is the violation of terms, the result is voiding of the warranty. Ends up meaning the same thing.