Request you to understand that no employer is ready to loose even a single employee as it is going to be very costly affair wrt replacement, the training part & specifically process / product part. It is the organizational culture & ethics of the employee.
I hope you have not seen the bigger world, in India & in Andhra Pradesh / Telengana there are "N"number of companies where the employees are working for more than 20 yrs in the same company.
In restricting such processes the HR role is very critical, if HR don't entertain the frequent flyers then employees shall not dare to leave the organizations frequently for salary hikes & higher positions.
Thanks and regards