We definitely received several notices all over the 'verse. I've been checking out multiple alternatives. The only way someone is unaware of the closure is if they're not active. In any case, what's to worry about? One day, some inactive users will not be able to log in to a closed instance. They'll have to join somewhere else.
I'll be honest, if I was off Lemmy for the week it was initially announced, I probably would have missed it. I haven't seen any notification in my app, or come across the sticky in my normal browsing.