Completely disable messaging while player is in Mobarena

[b74z]

I have tried (seemingly) everything to disable the message "[MobHunting] You don't get rewards while playing MobArena", but it still shows is some fashion. I have a (worldguard) region around my arena which is has the spawn region as its parent region. Everything works great there. However, when I join the arena (not opped), I keep getting spammed with messages about how I'm not receiving rewards. That's fine, and the intended outcome. I have played with the "mobhunting" worldguard flag, installed WGExtraFlags to set a entry/exit command to "mh mute", and I've also looked at the locale to see if I can just remove the message altogether. Is there an easier way to do this (if at all)?

MobHunting v 8.5.4
MobArena 0.108
WorldGuard 7.0.9

[b74z]

It might also be worth noting that the built-in MH WG flag works, and when the flag is set to "deny" the message changes to something like "You are in a region where mobhunting is disabled", which is just the same as before.