It's mentioned above, no? Holding salary as hostage until they move or resign. The other possible outcomes are not providing experience letters, acknowledging

It's mentioned above, no? Holding salary as hostage until they move or resign. The other possible outcomes are not providing experience letters, acknowledging employee worked, badmouthing, and harassing your next co-workers. Also, many big companies here do contracts with clauses that charges a service fee and take salary or bonus back if the worker doesn't work there for at least 2 years. If you leave soon, you might end up with negative pay. There are lots of potential ways to force this.