Currently there is no way to limit access to predefined vs custom warnings. The problem here is that moderators can add any number of warning points at their own discretion for a nonstandard violation. This undermines using standard warnings and warning actions. A preferred scenario is that you build a set of rules that if they are broken result in a set number of warning points per rule violation. If a certain number accumulate, a warning action happens. With the custom system, a moderator can define their own violation and any number of points, including crossing the threshold that could incur account limiting or banning. This would simply be done via a moderator permission. "Can assign custom warnings".