So I dropped an FYI via slack to a colleague and they immediately replied!

How dare they! They are on vacation!

Turn off your slack, disable your notification, don't check your mails.

Your work shouldn't have any impact on how you spend your vacation. We will manage.

FWIW, while some people burn themselves out by doing this crap, others almost find it weirdly comforting.

I know some who just keep half an eye on notifications while they're away because otherwise they just stress all the time that something could be going horribly wrong while they're not there. Now they *shouldn't* be doing that of course, but if you've got yourself into that mindset it can be hard to escape - and if glancing at the notifications once in a while can give you some peace of mind, so be it.

Try the schedule function and set the time to 9:00 on morning they get back (or maybe spread it out a bit).
You've still sent the info but they don't get it till they're in

Haha

I don't have Slack in my Android.
¯\_(ツ)_/¯

I love nothing more than banging in the DND and log off before holiday, it's the best.