Additionally, most rental car contracts specifically prohibit international travel, so even if you were able to take the car across the border, you would be in breach of the contract and any damages incurred would not be covered by insurance.
If you're looking to travel from LAX to Cabo San Lucas, there are various convenient and cost-effective options, including direct flights that take approximately 2.5 hours, as well as bus or shuttle transportation services that can take you over the border.