Players are still able to write, for example, in faction chat. Setting event priority to LOWEST would fix this issue.
Reference

Lowering it could cause unknown conflicts with other chat plugins. Perhaps it needs to be configurable instead.

Should /bmreload also reload the priority? I'm unsure of it working properly yet. You should probably also not put monitor there, since events shouldn't be cancelled at that level.

/bmreload does not reload the priority. It will add additional complexity. As for 'monitor', it's up to the user. Reloading via a plugin manager such as PlugMan should suffice.

Works perfectly then!