farci
I don't believe their are checks on departure ex UK for passengers travelling to any destination.
My arguments are
they'd need more staff, I doubt that the current government would fund this. Having experienced a two hour wait at Gatwick to enter the UK (overnight transfer) I wouldn't want to see fewer staff to check arrivals.
The airlines have the information (and this applies to all countries). Why not use the information that already exists before $pending for the infrastructure etc.
It's pointless, it doesn't support the goal of having people go home when they should be.