I always get annoyed on my warlock b/c I use a macro to mark my pet when I cast soul link and for some reason when you enter the arena it disables assist-all. My party lead always forgets to toggle it back on so I made a weak aura to enable assist-all whenever you are in an arena.
This allows the anyone in the group to place/update marks etc.
Example Mark Pet Macro: (Mark Pet as Skull)
/cast Soul Link
/script SetRaidTarget("pet", 8)
Known Issues: Sometimes the aura does not enable assist-all in arena. This appears to be due to an issue where GROUP_ROSTER_UPDATE don't fire for some reason. I should have a fix very soon for this. (11/18/2021)