Warning: New Call of Duty
They said prevention is better than cure. This note seems to convey a similar meaning. The writer took time to inform the neighborhood that he had just recently made an investment and acquired Call of Duty: Modern Warfare 3. With the note of “invest in some earplugs,” it can be said that he is implying that he can get carried away with video games and might create so much noise while playing.
The writer also noted that there is no need to call the cops “again.” This might be the reason why he already warned his neighbors before the same thing happened again. Good thing he already learned his lesson.