I haven't actually tried this myself, but from what I understand, iMessages will not show as delivered if you send to someone who has blocked you. You'll either get an error message, or it will send automatically as SMS (if Messages is configured to do that)... which will then be ignored by the phone at the other end.
As I recall they simply see it as being sent and possibly delivered (while you don't actually get it) and that's it. Meaning to them it's like they sent it as usual and you just never replied essentially.
So it will still say delivered? Are you 100% sure?
Not 100% without personally experimenting with it (which I haven't wanted/needed to do so far), but based on previous threads and various articles about this that I've come across in the past and recently (like the one at http://www.igeeksblog.com/how-to-know-if-someone-has-blocked-your-number-on-iphone/) it seems like that's the case.So it will still say delivered? Are you 100% sure?
They have an iPhone with the latest iOS.
No! there is no way for them to know they've been blocked. I, in the last 2-3 months, blocked a bunch of people from work. Yesterday, one of them asked if I received any of her messages because I wasn't responding and wanted to know if I was alright. She sent me an email; this is how I knew.
Based on another post from a thread dealing with this type of topic, yes, that's what it shows: https://forums.macrumors.com/showthread.php?p=18019732&postcount=3So it still says delivered?