@krishnakumarg
Brother you need to relax.
Just because YOU went for dual submission does not mean it is the right thing to do for everyone.
Agreed it is the last resort for someone who has messed up IDV app submission in the first place (
just to save time till UKVI contacts to book an appointment again) but NOT for everyone.
As Ameline said:
There is no need to give source as it is just common sense mate.
It is common sense. You have two options. Choose wisely.
If you choose IDV app submission AND then have second thoughts to go for UKVCAS appointment, it is NOT recommended.
If you do not want to choose IDV app submission, book a UKVCAS appointment in the first place.
Imagine everyone doing dual submissions; the whole IDV app concept fails.
However, claiming that "It is not recommended to do dual submission" absolutely needs to be backed up with formal evidence, unless it just the author's own informal opinion, and not an unequivocal statement summarising a published fact.
I am not writing a dissertation here. I am simply helping others with my own personal experience. I quote my opinion and everyone is free to follow it or not. If you want to write essays or thesis with citations and correct referencing, this forum is not the right place for you.