For some reason nofall, a hack where you don't take damage when falling, is allowed. I don't think it should be allowed, at least for hardcore because then you can't really die in any way. I thought of this bc when I was help build this guy parkour (who later tried to steal my grass twice) he was using nofall on his hardcore island.
Not in particular favor of this one, simply because for one, nofall isn't available to everyone. Just people with mod menus and such. If you're on hardcore, you don't have to use it either, but it's helpful in-case of tragic mistakes, lag, etc.
Like what bard said, with the lag we have at times on the server I can see why people use it. Whenever you randomly tp back or blocks re-appear and push you off.. I personally don’t think people should use it, but with the lag I can’t blame them.
It's not like you get a prize for succeeding at hardcore, so it's not cheating in any way. Hardcore is just a personal challenge if players want to play it, it's really their choice of how to play it.
To be honest I believe people that have hardcore island know what they are doing. They are in hardcore mode for a reason: to challenge themselves. It would defeat the point of players in hardcore mode to use nofall as they are only cheating themselves.
Support. You want the unvarnished glory of the Hardcore tag? You should be able to do what you gotta do.