1423 Roleen Drive is a corner house, so would be visible from not only neighboring properties along the same road, but several in the adjoining Alice Drive. This would only be of importance if the Zodiac Killer resided in one of the houses nearby and wanted the cheap thrill of watching the police visit the Tagert's property. However, this not only relies on the police visiting the Tagert's home address, but also necessitates the Zodiac Killer remaining at his residence throughout the relevant period. A threat to murder the couple would have been a far more effective tactic by the Zodiac Killer had he wanted to observe police activity around the property. It seemed that the Oakland A's tickets were of particular significance to the sender.
The fact that the tickets were accompanied by the message "GIFT FROM ZODIAC", as opposed to a direct threat on their lives, seems to suggest the purpose behind the communication lay at the Oakland Coliseum and the half-chance that the Zodiac Killer could observe the couple squirming in their seats. But without knowing what transpired on June 20th 1970, one can only speculate. I highly doubt the couple ever attended the baseball match because of the possible ramifications had anything unsavory occurred.
One of the main reasons for covering this topic is to understand the motive behind the mailing (if the Zodiac Killer), and get some other opinions. Why were the tickets added to the correspondence, if not to center the focus on the Oakland Coliseum?