they should have mentioned it clearly extending the line on the site itself that last date of online submission plus reaching delhi is 3rd september and what the site specifically mentions that 3rd september is last date for online submission. thats it.
and now the officials here from helping desk say it should reach delhi by 3rd sept and stringent policies and bla bla bla. you are managing top b school and can't focus on such things and you yourself mentioned that every year this happens. what a mess. so better be clear on site first and not on forums only next time.