I own a Samsung Galaxy S4, which has the Blocking mode feature. It is very useful because it mutes notification sounds during certain hours (I use it to automatically keep my phone quite while I'm sleeping).
It works perfectly for all the applications but WhatsApp. It seems to be a known issue, and I found a workaround that involved a led notification management application.
I don't like that solution because it is not clean and I'd like to find a better one. I come from the iOS world where all the applications are forced to pass through system notification center and I can't really get what's happening on my phone nor how WhatsApp can deliver me notifications.