Former IBM'er here. The reason IBM gives severance and extended benefits is not to look good, it's to prevent their employees from filing unlawful termination suits.
Second, there is a rumor in IBM that once an employee is marked as an RA (layoff), they are placed on an HR blacklist preventing them from finding another job internally. Departments that hire an employee placed on the RA blacklist are believed to have to layoff another employee to take their place.
I've only ever heard of one person being RA'd (she then went to Lenovo, and was eventually let go from there) and coming back. Now she's a manager at IBM again.
Second, there is a rumor in IBM that once an employee is marked as an RA (layoff), they are placed on an HR blacklist preventing them from finding another job internally. Departments that hire an employee placed on the RA blacklist are believed to have to layoff another employee to take their place.