Explanation
Check Point APIs let system administrators and developers make changes to the security policy with CLI tools and web-services. You can use an API to:
Use an automated script to perform common tasks
Integrate Check Point products with 3rd party solutions
Create products that use and enhance the Check Point solution
References:

Each instance of VRRP running on a supported interface may monitor the link state of other interfaces. The monitored interfaces do not have to be running VRRP. If a monitored interface loses its link state, then VRRP will decrement its priority over a VRID by the specified delta value and then will send out a new VRRP HELLO packet. If the new effective priority is less than the priority a backup platform has, then the backup platform will beging to send out its own HELLO packet. Once the master sees this packet with a priority greater than its own, then it releases the VIP.
Reference: https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk38524

Explanation/Reference:
Reference: https://sc1.checkpoint.com/documents/R80/CP_R80BC_ThreatPrevention/html_frameset.htm?
topic=documents/R80/CP_R80BC_ThreatPrevention/136486

Explanation/Reference:
Reference: http://slideplayer.com/slide/12183998/