Alright let's start on this possible long post.
Regedit, to Moderators and Sr. Moderators unaware of what it is, it's a setting inside Windows XP or higher which is able to increase your ping latency towards a server as well as negating lag. For example, I'm playing on Badlion, I use regedit, it helps with the pot lag I obtain and it makes my knockback negated a bit.
Gamma, I'm sure that every Moderator and Sr. Moderator should know what this is, but if they do not (hopefully they do) gamma is a modded client which increases the brightness of your Minecraft so that it is more visible to players.
Now, onto the main point. Should gamma be allowed and/or regedit be a punishable offense for using it. Gamma isn't much of an advantage in my opinion, yes it does make dark caves visible, but wouldn't that be the same for Windows user? For players using a Mac, their screen will occasionally be much much darker even on the highest setting for brightness their is, while Windows is already brighter by default. With this in mind, why can't gamma be allowed? I realize not everyone might realize how to increase it, but if say a staff member makes a guide on it, lots of users could easily learn and install gamma just like optifine. Another issue is that MCGamer has the gamemode, UHC, where mainly everyone on other servers that do allow gamma or UHC Essentials use. It's a client that everyone is able to easily download by searching a tutorial on Youtube.
With regedit, it may be hard to detect certain users using it but it should be a punishable offense in my opinion. It improves ping latency which isn't too bad, but the other side effects such as knockback. Knockback with regedit is reduced and sometimes it seems as if the user does not have any knockback, it's something that should be punishable as many players can take advantage of it by going in close, and killing the player with their improved ping and reduced knockback.
Anyways, I've written what needed to be written, and if possible, I would like Moderators and/or Sr. Moderators to discuss about a possibility of a rule change in the next meetings for Moderators and/or Sr. Moderators.