Dear Sir,
IF management creates circumstances and ask employee to resign just few months prior to completion of min. period required for maturity of gratuity; this is very wrong practice and such should not happen with anyone.
In some cases management have right to ceased gratuity of employee like misconduct in organization, fraud, intentionally behaviour against management's policy etc.
In case where management is forcing employee to leave company before completion gratuity eligibility in this case morally employee has right to ask management reason behind force to leave company and if that reason is valid then employee can go to labour office.