At the moment events are dispatched to observers of plugins even when the plugin is disabled, this is leading to situations where actions are being performed when they should not.

The only way a system administrator could work around a case like this would be to fully uninstall an affected plugin.

The current behaviour seems to be so unexpected that even plugins in core have not been checking if they are disabled before handling events, for example see MDL-71909.

It seems to me that it would be much better for Moodle to detect if plugins are enabled before sending an event.