Greetings,

It is not necessary to join the allotted seat per se but to ensure that students do not drop seat left and right, some rules have been put in place regarding this.

Firstly, you will lose the seat if you don't report to the allotted college. You will also not be allowed to sit for further rounds of counselling and will lose the security deposit.

I a attaching an official FAQ link regarding this for your understanding,

https://mcc.nic.in/PGCounselling/home/ShowPdf?Type=50C9E8D5FC98727B4BBC93CF5D64A68DB647F04F&ID=6FB84AED32FACD1299EE1E77C8FD2B1A6352669E

good luck