Late Loading Plugins
Late loading a plugin means manually loading the plugin to the server after the initial default plugin loading process of sourcemod ( either an admin or another plugin does the late loading )
The pro in making your plugin possible to late load is the ability to load the plugin without changing a map.
The most common thing preventing plugins from late loading properly is anything done within OnClientPutInServer and OnClientPostAdminCheck, as these forwards do not fire when a plugin is late loaded.